Functionalized n-acetylgalactosamine analogs

ABSTRACT

Embodiments of the present application relate to functionalized N-acetylgalactosamine-analogs, methods of making, and uses of the same. In particular, mono or trivalent N-acetylgalactosamine analogs may be prepared by utilizing a wide variety of linkers containing functional groups. These functionalized N-acetylgalactosamine-analogs may be used in the preparation of targeted delivery of oligonucleotide-based therapeutics.

FIELD

The present application relates to functionalized N-acetylgalactosamine analogs and their methods of preparation. More specifically, the present application relates to compounds having N-acetylgalactosamine moieties conjugated to a moiety having multiple functional groups using a variety of linkers. The functionalized N-acetylgalactosamine analogs disclosed herein may be used for targeted in vivo delivery of oligonucleotide-based therapeutics.

REFERENCE TO SEQUENCE LISTING

The present application is being filed along with a Sequence Listing in electronic format. The Sequence Listing is provided as a file entitled “HGENE_008D1_Sequence_Listing.xml” created on May 18, 2023, which is 1.95 KB in size. The information in the electronic format of the Sequence Listing is incorporated herein by reference in its entirety.

BACKGROUND Description of the Related Art

Oligonucleotide-based drugs have become a powerful epitome having ability to treat various diseases. N-acetylgalactosamine (GalNAc) is a well-defined liver-targeted moiety benefiting from its high affinity with asialoglycoprotein receptor (ASGPR). It can facilitate uptake and clearance of circulating GalNAc-conjugated oligo via clathrin-mediated endocytosis. The strongest attribute of GalNAc conjugates, compared to other oligo conjugates, is the internalization and cellular trafficking efficiency, which enables near-complete mRNA knockdown at exceedingly low doses in preclinical species and human subjects. This differentiating factor is related to the high membrane density of the ASGPR on hepatocytes and the rapid cycle in which it internalizes and recycles back to the cell surface. Only 15 mins are required for ASGPR internalization and recycling to the cell surface.

ASGPR consists of two homologous subunits, designated H1 and H2 in the human system, which form a non-covalent heterooligomeric complex with estimated ratios of 2:1 and 5:1, respectively. Both subunits are single-spanning membrane proteins with a calcium-dependent Gal/GalNAc recognition domain (CRDs). On the native receptor on the hepatocyte surface these binding sites are 25-30 Å apart. All conjugations of mono-, di-, tri-, or tetra-GalNAc sugars can enhance the delivery efficiency of oligonucleotides to hepatocytes. Binding hierarchy of polyvalent ligands is: tetraantennary>triantennary>>diantennary>>monoantennary. Since the fourth GalNAc moiety present in the tetraantennary ligand does not markedly enhance the affinity, it was presumed that the binding requirements of the cell-surface receptor are largely saturated by the triantennary structure. Scientists have reached a consensus that triantennary GalNAc analogs with a mutual distance of 20 Å exhibit the highest affinity with ASGPR.

Trivalent and monovalent GalNAc analogs have been previously reported. Oligonucleotide therapeutics have pharmacological challenges including susceptibility to nuclease-mediated degradation, rapid elimination, poor biodistribution, insufficient membrane permeability, immune stimulation, and potentially significant off-target effects. Accordingly, a need exists for preparing novel functionalized GalNAc analogs to improve drug delivery.

SUMMARY

Some aspect of the present disclosure relates to compounds of Formula (I):

or a pharmaceutically acceptable salt thereof; wherein

-   -   each of R¹, R², and R³ is independently hydrogen, benzyl, or         —C(═O)R⁸;     -   R⁴ is —C(═O)C₁₋₆ alkyl or —C(═O)C₁₋₆ haloalkyl;     -   R⁵ is a hydroxy protecting group;     -   R⁶ is hydrogen, a phosphoramidite moiety,         —C(═O)CH₂CH₂C(═O)R^(6A), or —P(OR^(6B))NR^(6C)R^(6D);     -   Y¹ is NR⁷, *NR⁷C(═O), or O, the asterisk * indicates that Y¹ is         connected to L³ through the nitrogen atom of Y¹, provided that         when Y¹ is *NR⁷C(═O), then L⁴ is absent;     -   Z¹ is C(R^(Z)), P(═S), P(═O) or N, wherein R^(Z) is hydrogen or         unsubstituted C₁₋₆ alkyl, provided that when Z¹ is N, both L⁴         and Y¹ are absent;     -   each of L¹, L², and L³ is independently a bond, —C(═O)—,         —C(═S)—, —S(═O)₂—, —C(═O)NR⁹—, —C(═S)NR⁹—, —C(═O)O—, —C(═S)O—,         —NR⁹C(═O)NR⁹—, —NR⁹C(═S)NR⁹—, —OP(═O)(OH)O—, —OP(═S)(OH)O—, —O—,         —S—, —NR⁹—, optionally substituted C₁₋₁₀ alkylene, optionally         substituted C₆₋₁₀ arylene, optionally substituted C₃₋₁₀         cycloalkylene, optionally substituted 5-10 membered         heteroarylene, optionally substituted 5 to 10 membered         heterocyclylene, or optionally substituted 2 to 15 membered         heteroalkylene wherein one or more carbon atoms are replaced         with C(═O), O, S or N, provided that at least one of L¹, L², and         L³ is not a bond;     -   L⁴ is optionally substituted C₁₋₈ alkylene;     -   each of R⁷ and R⁹ is independently hydrogen, unsubstituted C₁₋₆         alkyl, substituted C₁₋₆ alkyl, or an amino protecting group;     -   each R⁸ is independently C₁₋₆ alkyl, C₁₋₆ haloalkyl, or         optionally substituted phenyl;     -   R^(6A) is —OH, —OR¹⁰ or —NR¹¹R¹².     -   each of R^(6B), R^(6C) and R^(6D) is independently H, C₁₋₆         haloalkyl, or unsubstituted or substituted C₁₋₆ alkyl;     -   R¹⁰ is unsubstituted or substituted C₁₋₆ alkyl, or a hydroxy         protecting group;     -   each of R¹¹ and R¹² is independently H, unsubstituted or         substituted C₁₋₆ alkyl, or an amino protecting group; and     -   each of m and n is independently 0, 1, 2 or 3, provided that m         and n cannot both be 0.         In some embodiments, when -L¹-L²-L³- comprise one or more C(═O),         Y¹ is NR⁷, Z¹ is C(R^(Z)), and m+n=1; then R^(Z) is         unsubstituted C₁₋₆ alkyl. In some embodiments, when         -L¹-L²-L³-comprise one or more C(═O), Y¹ is NR⁷, and m+n=1; then         Z¹ is P(═O), P(═S) or C(R^(Z)), where R^(Z) is unsubstituted         C₁₋₆ alkyl.

In some embodiments, compounds of Formula (I) have the structure of Formula (Ia):

or a pharmaceutically acceptable salt thereof.

In some embodiments, compounds of Formula (I) have the structure of Formula (Ib):

or a pharmaceutically acceptable salt thereof.

Some aspect of the present disclosure relates to compounds of Formula (II):

or a pharmaceutically acceptable salt thereof, wherein

-   -   each of R^(1a), R^(1b), R^(1c), R^(2a), R^(2b), R^(2c), R^(3a),         R^(3b), and R^(3c) is independently hydrogen, benzyl, or         —C(═O)R⁸;     -   each of R^(4a), R^(4b) and R^(4c) is independently —C(═O)C₁₋₆         alkyl or —C(═O)C₁₋₆ haloalkyl;     -   R⁵ is a hydroxy protecting group;     -   R⁶ is hydrogen, a phosphoramidite moiety,         —C(═O)CH₂CH₂C(═O)R^(6A), or —P(OR^(6B))NR^(6C)R^(6D);     -   Y² is absent, NR⁷, *NR⁷C(═O) or O, the asterisk * indicates that         Y² is connected to L⁵ through the nitrogen atom of Y², provided         that when Y² is *NR⁷C(═O), then L⁴ is absent;     -   Z² is C(R^(Z)), P(═S), P(═O) or N, wherein R^(Z) is hydrogen or         unsubstituted C₁₋₆ alkyl, provided that when Z² is N, both L⁴         and Y² are absent;     -   each of X¹, X² and X³ is independently —O(CH₂)₁₋₃—,         —NH(CH₂)₁₋₃—, —C(═O)(CH₂)₁₋₃— or —NHC(═O)(CH₂)₁₋₃—;     -   each of L^(1a), L^(1b), L^(1c), L^(2a), L^(2b), L^(2c), L^(3a),         L^(3b), and L^(3c) is independently a bond, —C(═O)—, —C(═S)—,         —S(═O)₂—, —C(═O)NR⁹—, —C(═S)NR⁹—, —C(═O)O—, —C(═S)O—,         —NR⁹C(═O)NR⁹—, —NR⁹C(═S)NR⁹—, —OP(═O)(OH)O—, —OP(═S)(OH)O—, —O—,         —S—, —NR⁹—, optionally substituted C₁₋₁₀ alkylene, optionally         substituted C₆₋₁₀ arylene, optionally substituted C₃₋₁₀         cycloalkylene, optionally substituted 5-10 membered         heteroarylene, optionally substituted 5 to 10 membered         heterocyclylene, or optionally substituted 2 to 15 membered         heteroalkylene wherein one or more carbon atoms are replaced         with C(═O), O, S or N, provided that at least one of L^(1a),         L^(1b) and L^(1c) is not a bond, at least one of L^(2a), L^(2b)         and L^(2c) is not a bond, and at least one of L^(3a), L^(3b) and         L^(3c) is not a bond;     -   L⁴ is optionally substituted C₁₋₈ alkylene or         —(CH₂)₁₋₃(OCH₂CH₂)₁₋₅OCH₂—;     -   L⁵ is absent, optionally substituted C₁₋₁₀ alkylene, or         optionally substituted 2 to 15 membered heteroalkylene wherein         one or more carbon atoms are replaced with C(═O), O, S or N;     -   each of R⁷ and R⁹ is independently hydrogen, unsubstituted C₁₋₆         alkyl, substituted C₁₋₆ alkyl, or an amino protecting group;     -   each R⁸ is independently C₁₋₆ alkyl, C₁₋₆ haloalkyl, or         optionally substituted phenyl;     -   R^(6A) is —OH, —OR¹⁰ or —NR¹¹R¹²;     -   each of R^(6B), R^(6C) and R^(6D) is independently H, C₁₋₆         haloalkyl, or unsubstituted or substituted C₁₋₆ alkyl;     -   R¹⁰ is unsubstituted or substituted C₁₋₆ alkyl, or a hydroxy         protecting group;     -   each of R¹¹ and R¹² is independently H, unsubstituted or         substituted C₁₋₆ alkyl, or an amino protecting group;     -   each of m and n is independently 0, 1, 2 or 3, provided that m         and n cannot both be 0; and     -   k is 0 or 1. In some embodiments, when L⁵ is present and         comprises one or more C(═O), Y² is NR⁷, Z¹ is C(R^(Z)), and         m+n=1; then R^(Z) is unsubstituted C₁₋₆ alkyl. In some         embodiments, when L⁵ comprise one or more C(═O), Y² is NR⁷, and         m+n=1; then Z² is P(═O), P(═S) or C(R^(Z)), where R^(Z) is         unsubstituted C₁₋₆ alkyl.

In some embodiments, compounds of Formula (II) have the structure of Formula (IIa):

or a pharmaceutically acceptable salt thereof.

In some embodiments, compounds of Formula (II) have the structure of Formula (IIb):

or a pharmaceutically acceptable salt thereof.

In some embodiments, compounds of Formula (II) have the structure of Formula (IIc):

or a pharmaceutically acceptable salt thereof.

In some embodiments, compounds of Formula (II) have the structure of Formula (IId):

or a pharmaceutically acceptable salt thereof, wherein

-   -   each of X¹, X² and X³ is —OCH₂— or —NHCH₂—, or each of X¹ and X³         is —C(═O)CH₂CH₂—, and X² is —C(═O)CH₂—, or each of X¹ and X³ is         —NHC(═O)CH₂CH₂—, and X² is —NHC(═O)CH₂—;     -   Y² is NH, *NH(C═O), O or absent;

and

-   -   R⁶ is —C(═O)CH₂CH₂C(═O)OH or

A further aspect of the present disclosure relates to a solid support comprising a compound described herein of Formula (I), (Ia), (Ib), (II), (IIa), (IIb), (IIc) or (IId) covalently attached thereto via R⁶. In some embodiments, R⁶ is —C(═O)CH₂CH₂C(═O)OH. In further embodiments, the compound is covalently attached to the solid support via a moiety:

wherein the dashed line refers to the connection with the solid support, optionally through an additional linker, and wherein the squiggly line refers to the point of the attachment of the oxygen atom that covalently attached to R⁶ of the compound, to the remaining portion of the compound.

Additional aspect of the present disclosure relates to a method of preparing a synthetic oligonucleotide, comprising reacting a compound described herein of Formula (I), (Ia), (Ib), (II), (IIa), (IIb), (IIc) or (IId) with an oligonucleotide. In some embodiments, the oligonucleotide may have a 1 to 100 nucleobase length. In some embodiments, the reaction may be conducted on a solid support.

DETAILED DESCRIPTION

The compounds disclosed herein relate to novel functionalized GalNAc analogs to provide novel methods for oligonucleotide delivery. In some embodiments, the functionalized GalNAc analogs disclosed herein may contain a phosphoramidite moiety that allows for the incorporation of the GalNAc analogs to the 5′ end or any internal position of an oligonucleotide. In some other embodiments, the functionalized GalNAc analogs disclosed herein may contain a succinate moiety that allows for the incorporation of the GalNAc analogs on a solid support, which can introduce GalNAc analogs described herein to the 3′ end of oligonucleotide.

Definitions

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art. All patents, applications, published applications and other publications referenced herein are incorporated by reference in their entirety unless stated otherwise. In the event that there are a plurality of definitions for a term herein, those in this section prevail unless stated otherwise. As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Unless otherwise indicated, conventional methods of mass spectroscopy, NMR, HPLC, protein chemistry, biochemistry, recombinant DNA techniques and pharmacology are employed. The use of “or” or “and” means “and/or” unless stated otherwise. Furthermore, use of the term “including” as well as other forms, such as “include”, “includes,” and “included,” is not limiting.

While the disclosure has been illustrated and described in detail in the foregoing description, such description is to be considered illustrative or exemplary and not restrictive. The disclosure is not limited to the disclosed embodiments. Variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed disclosure, from a study of the disclosure and the appended claims.

All references cited herein are incorporated herein by reference in their entirety. To the extent publications and patents or patent applications incorporated by reference contradict the disclosure contained in the specification, the specification is intended to supersede and/or take precedence over any such contradictory material.

Unless otherwise defined, all terms (including technical and scientific terms) are to be given their ordinary and customary meaning to a person of ordinary skill in the art, and are not to be limited to a special or customized meaning unless expressly so defined herein. It should be noted that the use of particular terminology when describing certain features or aspects of the disclosure should not be taken to imply that the terminology is being re-defined herein to be restricted to include any specific characteristics of the features or aspects of the disclosure with which that terminology is associated.

Where a range of values is provided, it is understood that the upper and lower limit, and each intervening value between the upper and lower limit of the range is encompassed within the embodiments.

As used herein, any “R” group(s) represent substituents that can be attached to the indicated atom. An R group may be substituted or unsubstituted. If two “R” groups are described as being “taken together” the R groups and the atoms they are attached to can form a cycloalkyl, aryl, heteroaryl, or heterocycle. For example, without limitation, if R^(a) and R^(b), and the atom to which it is attached, are indicated to be “taken together” or “joined together” it means that they are covalently bonded to one another to form a ring:

Whenever a group is described as being “optionally substituted” that group may be unsubstituted or substituted with one or more of the indicated substituents. Likewise, when a group is described as being “substituted”, the substituent may be selected from one or more of the indicated substituents. If no substituents are indicated, it is meant that the indicated “optionally substituted” or “substituted” group may be one or more group(s) individually and independently selected from alkyl (e.g., C₁-C₆ alkyl); alkenyl (e.g., C₂-C₆ alkenyl); alkynyl (e.g., C₂-C₆ alkynyl); C₃-C₈ carbocyclyl (for example, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkenyl, or C₃-C₈ cyclalkynyl, each may further be optionally substituted, for example, with halo, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkyl, C₁-C₆ haloalkoxy, (C₁-C₆ alkoxy)C₁-C₆ alkyl, or —O(C₁-C₆ alkoxy)C₁-C₆ alkyl); (C₃-C₇ carbocyclyl)C₁-C₆ alkyl (may further be optionally substituted, for example, with halo, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkyl, C₁-C₆ haloalkoxy, (C₁-C₆ alkoxy)C₁-C₆ alkyl, or —O(C₁-C₆ alkoxy)C₁-C₆ alkyl); 5-10 membered heterocyclyl (may further be optionally substituted, for example, with halo, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkyl, C₁-C₆ haloalkoxy, (C₁-C₆ alkoxy)C₁-C₆ alkyl, or —O(C₁-C₆ alkoxy)C₁-C₆ alkyl); (5-10 membered heterocyclyl)C₁-C₆ alkyl (may further be optionally substituted, for example, with halo, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkyl, C₁-C₆ haloalkoxy, (C₁-C₆ alkoxy)C₁-C₆ alkyl, or —O(C₁-C₆ alkoxy)C₁-C₆ alkyl); aryl (may further be optionally substituted, for example, with halo, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkyl, C₁-C₆ haloalkoxy, (C₁-C₆ alkoxy)C₁-C₆ alkyl, or —O(C₁-C₆ alkoxy)C₁-C₆ alkyl); (aryl)C₁-C₆ alkyl (may further be optionally substituted, for example, with halo, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkyl, C₁-C₆ haloalkoxy, (C₁-C₆ alkoxy)C₁-C₆ alkyl, or —O(C₁-C₆ alkoxy)C₁-C₆ alkyl); 5-10 membered heteroaryl (may further be optionally substituted with halo, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkyl, C₁-C₆ haloalkoxy, (C₁-C₆ alkoxy)C₁-C₆ alkyl, or —O(C₁-C₆ alkoxy)C₁-C₆ alkyl); (5-10 membered heteroaryl)C₁-C₆ alkyl (may further be optionally substituted with halo, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₁-C₆ haloalkyl, C₁-C₆ haloalkoxy, (C₁-C₆ alkoxy)C₁-C₆ alkyl, or —O(C₁-C₆ alkoxy)C₁-C₆ alkyl); halo (e.g., fluoro, chloro, bromo, iodo); cyano; hydroxy; protected hydroxy; alkoxy (e.g., C₁-C₆ alkoxy); haloalkyl (e.g., C₁-C₆ haloalkyl, such as —CF₃); haloalkyl (e.g., C₁-C₆ haloalkoxy such as —OCF₃); (C₁-C₆ alkoxy)C₁-C₆ alkyl; —O(C₁-C₆ alkoxy)C₁-C₆ alkyl; (C₁-C₆ haloalkoxy)C₁-C₆ alkyl; —O(C₁-C₆ haloalkoxy)C₁-C₆ alkyl; aryloxy; sulfhydryl (mercapto); alkylthio (e.g., C₁-C₆ alkylthio); arylthio; azido; nitro; O-carbamyl; N-carbamyl; O-thiocarbamyl; N-thiocarbamyl; C-amido; N-amido; S-sulfonamido; N-sulfonamido; C-carboxy; protected C-carboxy; O-carboxy; acyl; cyanate; isocyanato; thiocyanato; isothiocyanato; silyl; sulfenyl; sulfinyl; sulfonyl; trihalomethanesulfonyl; trihalomethanesulfonamido; amino (including protected derivatives thereof); mono-substituted amino (for example, NH(C₁-C₆ alkyl); di-substituted amino (for example, N(C₁-C₆ alkyl)₂); oxo (═O); and thioxo (═S).

As used herein, “C_(a) to C_(b)” in which “a” and “b” are integers refer to the number of carbon atoms in an alkyl group, or the number of ring atoms of a cycloalkyl, aryl, heteroaryl or heterocyclyl group. That is, the alkyl, ring of the cycloalkyl, and ring of the aryl, can contain from “a” to “b”, inclusive, carbon atoms. Likewise, the ring of the heteroaryl and ring of the heterocyclyl can contain from “a” to “b”, inclusive, total ring atoms. Thus, for example, a “C₁ to C₄ alkyl” group refers to all alkyl groups having from 1 to 4 carbons, that is, CH₃—, CH₃CH₂—, CH₃CH₂CH₂—, (CH₃)₂CH—, CH₃CH₂CH₂CH₂—, CH₃CH₂CH(CH₃)— and (CH₃)₃C—; a C₃ to C₄ cycloalkyl group refers to all cycloalkyl groups having from 3 to 4 carbon atoms, that is, cyclopropyl and cyclobutyl. Similarly, a “4 to 6 membered heterocyclyl” group refers to all heterocyclyl groups with 4 to 6 total ring atoms, for example, azetidine, oxetane, oxazoline, pyrrolidine, piperidine, piperazine, morpholine, and the like. If no “a” and “b” are designated with regard to an alkyl, cycloalkyl, aryl, heteroaryl or heterocyclyl group, the broadest range described in these definitions is to be assumed. As used herein, the term “C₁-C₆” includes C₁, C₂, C₃, C₄, C₅ and C₆, and a range defined by any of the two numbers. For example, C₁-C₆ alkyl includes C₁, C₂, C₃, C₄, C₅ and C₆ alkyl, C₂-C₆ alkyl, C₁-C₃ alkyl, etc. Similarly, C₃-C₈ carbocyclyl or cycloalkyl each includes hydrocarbon ring containing 3, 4, 5, 6, 7 and 8 carbon atoms, or a range defined by any of the two numbers, such as C₃-C₇ cycloalkyl or C₅-C₆ cycloalkyl.

As used herein, “alkyl” refers to a straight or branched hydrocarbon chain that comprises a fully saturated (no double or triple bonds) hydrocarbon group. The alkyl group may have 1 to 20 carbon atoms (whenever it appears herein, a numerical range such as “1 to 20” refers to each integer in the given range; e.g., “1 to 20 carbon atoms” means that the alkyl group may consist of 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc., up to and including 20 carbon atoms, although the present definition also covers the occurrence of the term “alkyl” where no numerical range is designated). The alkyl group may also be a medium size alkyl having 1 to 10 carbon atoms. The alkyl group could also be a lower alkyl having 1 to 6 carbon atoms. The alkyl group of the compounds may be designated as “C₁-C₄ alkyl” or similar designations. By way of example only, “C₁-C₄ alkyl” indicates that there are one to four carbon atoms in the alkyl chain, i.e., the alkyl chain is selected from methyl, ethyl, propyl, iso-propyl, n-butyl, iso-butyl, sec-butyl, and t-butyl. Typical alkyl groups include, but are in no way limited to, methyl, ethyl, n-propyl, isopropyl, butyl, isobutyl, tertiary butyl, pentyl (straight chain or branched), and hexyl (straight chain or branched). The alkyl group may be substituted or unsubstituted.

As used herein, “alkenyl” refers to a straight or branched hydrocarbon chain containing one or more double bonds. The alkenyl group may have 2 to 20 carbon atoms. By way of example only, “C₂-C₆ alkenyl” indicates that there are two to six carbon atoms in the alkenyl chain, i.e., the alkenyl chain is selected from the group consisting of ethenyl, propen-1-yl, propen-2-yl, propen-3-yl, buten-1-yl, buten-2-yl, buten-3-yl, buten-4-yl, 1-methyl-propen-1-yl, 2-methyl-propen-1-yl, 1-ethyl-ethen-1-yl, 2-methyl-propen-3-yl, buta-1,3-dienyl, buta-1,2,-dienyl, and buta-1,2-dien-4-yl. Typical alkenyl groups include, but are in no way limited to, ethenyl, propenyl, butenyl, pentenyl, and hexenyl, and the like. The alkenyl group may be substituted or unsubstituted.

As used herein, “alkynyl” refers to a straight or branched hydrocarbon chain containing one or more triple bonds. The alkynyl group may have 2 to 20 carbon atoms. By way of example only, “C₂-C₄ alkynyl” indicates that there are two to six carbon atoms in the alkynyl chain, i.e., the alkynyl chain is selected from the group consisting of ethynyl, propyn-1-yl, propyn-2-yl, butyn-1-yl, butyn-3-yl, butyn-4-yl, and 2-butynyl. Typical alkynyl groups include, but are in no way limited to, ethynyl, propynyl, butynyl, pentynyl, and hexynyl, and the like. The alkynyl group may be substituted or unsubstituted.

As used herein, “cycloalkyl” refers to a completely saturated (no double or triple bonds) mono- or multi-cyclic hydrocarbon ring system. When composed of two or more rings, the rings may be joined together in a fused, bridged or spiro fashion. As used herein, the term “fused” refers to two rings which have two atoms and one bond in common. As used herein, the term “bridged cycloalkyl” refers to compounds wherein the cycloalkyl contains a linkage of one or more atoms connecting non-adjacent atoms. As used herein, the term “spiro” refers to two rings which have one atom in common and the two rings are not linked by a bridge. Cycloalkyl groups can contain 3 to 10 atoms in the ring(s), 3 to 8 atoms in the ring(s), or 3 to 6 atoms in the ring(s). A cycloalkyl group may be unsubstituted or substituted. Examples of monocyclic cycloalkyl groups include, but are in no way limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl. Examples of bicyclic fused cycloalkyl groups are decahydronaphthalenyl, dodecahydro-1H-phenalenyl and tetradecahydroanthracenyl; examples of bicyclic bridged cycloalkyl groups are bicyclo[1.1.1]pentyl, adamantanyl and norbornanyl; and examples of bicyclic spiro cycloalkyl groups include spiro[3.3]heptane and spiro[4.5]decane.

As used herein, “carbocyclyl” refers to a non-aromatic a mono- or multi-cyclic hydrocarbon ring system. When composed of two or more rings, the rings may be joined together in a fused, bridged or spiro fashion, as described herein. Carbocyclyl groups can contain 3 to 30 atoms in the ring(s), 3 to 20 atoms in the ring(s), 3 to 10 atoms in the ring(s), 3 to 8 atoms in the ring(s) or 3 to 6 atoms in the ring(s). A carbocyclyl group may be unsubstituted or substituted. Examples of carbocyclyl groups include, but are in no way limited to, cycloalkyl groups, as defined herein, and the non-aromatic portions of 1,2,3,4-tetrahydronaphthalene, 2,3-dihydro-1H-indene, 5,6,7,8-tetrahydroquinoline and 6,7-dihydro-5H-cyclopenta[b]pyridine.

As used herein, “aryl” refers to a carbocyclic (all carbon) monocyclic or multicyclic aromatic ring system (including fused ring systems where two carbocyclic rings share a chemical bond) that has a fully delocalized pi-electron system throughout all the rings. The number of carbon atoms in an aryl group can vary. For example, the aryl group can be a C₆ aryl group, or a C₁₀ aryl group. Examples of aryl groups include, but are not limited to, benzene and naphthalene. An aryl group may be substituted or unsubstituted.

As used herein, “heteroaryl” refers to a monocyclic or multicyclic aromatic ring system (a ring system with fully delocalized pi-electron system) that contain(s) one or more heteroatoms (for example, 1, 2 or 3 heteroatoms), that is, an element other than carbon, including but not limited to, nitrogen, oxygen and sulfur. The number of atoms in the ring(s) of a heteroaryl group can vary. For example, the heteroaryl group can contain 5 to 10 atoms in the ring(s), 6 to 10 atoms in the ring(s) or 5 to 6 atoms in the ring(s), such as nine carbon atoms and one heteroatom; eight carbon atoms and two heteroatoms; seven carbon atoms and three heteroatoms; eight carbon atoms and one heteroatom; seven carbon atoms and two heteroatoms; six carbon atoms and three heteroatoms; five carbon atoms and four heteroatoms; five carbon atoms and one heteroatom; four carbon atoms and two heteroatoms; three carbon atoms and three heteroatoms; four carbon atoms and one heteroatom; three carbon atoms and two heteroatoms; or two carbon atoms and three heteroatoms. Furthermore, the term “heteroaryl” includes fused ring systems where two rings, such as at least one aryl ring and at least one heteroaryl ring or at least two heteroaryl rings, share at least one chemical bond. Examples of heteroaryl rings include, but are not limited to, furan, furazan, thiophene, benzothiophene, phthalazine, pyrrole, oxazole, benzoxazole, 1,2,3-oxadiazole, 1,2,4-oxadiazole, thiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole, benzothiazole, imidazole, benzimidazole, indole, indazole, pyrazole, benzopyrazole, isoxazole, benzoisoxazole, isothiazole, triazole, benzotriazole, thiadiazole, tetrazole, pyridine, pyridazine, pyrimidine, pyrazine, purine, pteridine, quinoline, isoquinoline, quinazoline, quinoxaline, cinnoline and triazine. A heteroaryl group may be substituted or unsubstituted.

As used herein, “heterocyclyl” refers to three-, four-, five-, six-, seven-, eight-, nine-, and ten-membered monocyclic, bicyclic and tricyclic ring system wherein carbon atoms together with from 1 to 5 heteroatoms constitute said ring system. A heterocycle may optionally contain one or more unsaturated bonds situated in such a way, however, that a fully delocalized pi-electron system does not occur throughout all the rings (i.e., heterocyclyl groups are not aromatic). The heteroatom(s) is an element other than carbon including, but not limited to, oxygen, sulfur and nitrogen. A heterocycle may further contain one or more carbonyl functionalities, so as to make the definition include oxo-systems such as lactams, lactones, and cyclic carbamates. When composed of two or more rings, the rings may be joined together in a fused, bridged or spiro fashion. As used herein, the term “fused” refers to two rings which have two atoms and one bond in common. As used herein, the term “bridged heterocyclyl” refers to compounds wherein the heterocyclyl contains a linkage of one or more atoms connecting non-adjacent atoms. As used herein, the term “spiro” refers to two rings which have one atom in common and the two rings are not linked by a bridge. Heterocyclyl groups can contain 3 to 10 atoms in the ring(s), 3 to 8 atoms in the ring(s), 3 to 6 atoms in the ring(s), or 5 to 6 atoms in the ring(s). For example, five carbon atoms and one heteroatom; four carbon atoms and two heteroatoms; three carbon atoms and three heteroatoms; four carbon atoms and one heteroatom; three carbon atoms and two heteroatoms; two carbon atoms and three heteroatoms; one carbon atom and four heteroatoms; three carbon atoms and one heteroatom; or two carbon atoms and one heteroatom. Additionally, any nitrogen in a heterocyclyl group may be quaternized. Heterocyclyl groups can be linked to the rest of the molecule via a carbon atom in the heterocyclyl group (C-linked) or by a heteroatom in the heterocyclyl group, such as a nitrogen atom (N-linked). Heterocyclyl groups may be unsubstituted or substituted. Examples of such “heterocyclyl” groups include but are not limited to, aziridine, oxirane, thiirane, azetidine, oxetane, 1,3-dioxin, 1,3-dioxane, 1,4-dioxane, 1,2-dioxolane, 1,3-dioxolane, 1,4-dioxolane, 1,3-oxathiane, 1,4-oxathiin, 1,3-oxathiolane, 1,3-dithiole, 1,3-dithiolane, 1,4-oxathiane, tetrahydro-1,4-thiazine, 2H-1,2-oxazine, maleimide, succinimide, barbituric acid, thiobarbituric acid, dioxopiperazine, hydantoin, dihydrouracil, trioxane, hexahydro-1,3,5-triazine, imidazoline, imidazolidine, isoxazoline, isoxazolidine, oxazoline, oxazolidine, oxazolidinone, thiazoline, thiazolidine, morpholine, oxirane, piperidine N-oxide, piperidine, piperazine, pyrrolidine, azepane, pyrrolidone, pyrrolidione, 4-piperidone, pyrazoline, pyrazolidine, 2-oxopyrrolidine, tetrahydropyran, 4H-pyran, tetrahydrothiopyran, thiamorpholine, thiamorpholine sulfoxide, thiamorpholine sulfone and their benzo-fused analogs (e.g., benzimidazolidinone, tetrahydroquinoline and/or 3,4-methylenedioxyphenyl). Examples of spiro heterocyclyl groups include 2-azaspiro[3.3]heptane, 2-oxaspiro[3.3]heptane, 2-oxa-6-azaspiro[3.3]heptane, 2,6-diazaspiro[3.3]heptane, 2-oxaspiro[3.4]octane and 2-azaspiro[3.4]octane.

As used herein, “alkylene” refers to a branched, or straight chain fully saturated di-radical chemical group containing only carbon and hydrogen that is attached to the rest of the molecule via two points of attachment. By way of example only, “C₁-C₁₀ alkylene” indicates that there are one to ten carbon atoms in the alkylene chain. Non-limiting examples include ethylene (—CH₂CH₂—), propylene (—CH₂CH₂CH₂—), butylene (—CH₂CH₂CH₂CH₂—), and pentylene (—CH₂CH₂CH₂CH₂CH₂—).

As used herein, “alkenylene” refers to a straight or branched chain di-radical chemical group containing only carbon and hydrogen and containing at least one carbon-carbon double bond that is attached to the rest of the molecule via two points of attachment. The alkenylene group may be designated as “C₂-C₁₀ alkenylene” or similar designations. By way of example only, “C₂-C₁₀ alkenylene” indicates that there are two to ten carbon atoms in the alkenylene chain.

As used herein, “alkynylene” refers to a straight or branched chain di-radical chemical group containing only carbon and hydrogen and containing at least one carbon-carbon triple bond that is attached to the rest of the molecule via two points of attachment. The alkynylene group may be designated as “C₂-C₁₀ alkenylene” or similar designations. By way of example only, “C₂-C₁₀ alkynylene” indicates that there are two to ten carbon atoms in the alkynylene chain.

As used herein, “heteroalkylene” refers to an alkylene group, as defined herein, containing one or more heteroatoms in the carbon back bone (i.e., an alkylene group in which one or more carbon atoms is replaced with a heteroatom, for example, nitrogen atom (N), oxygen atom (S) or sulfur atom (S)). For example, a —CH₂— may be replaced with —O—, —S—, or —NH—. Heteroalkylene groups include, but are not limited to ether, thioether, amino-alkylene, and alkylene-amino-alkylene moieties. In some embodiments, the heteroalkylene may include one, two, three, four, or five —CH₂CH₂O— unit(s). Alternatively and/or additionally, one or more carbon atoms can also be substituted with an oxo (═O) to become a carbonyl. For example, a —CH₂— may be replaced with —C(═O)—. It is understood that when a carbon atom is replaced with a carbonyl group, it refers to the replacement of —CH₂— with —C(═O)—. When a carbon atom is replaced with a nitrogen atom, it refers to the replacement of —CH— with —N—. When a carbon atom is replaced with an oxygen or sulfur atom, it refers to the replacement of —CH₂— with —O— or —S—.

As used herein, “aralkyl” and “(aryl)alkyl” refer to an aryl group, as defined above, connected, as a substituent, via an alkylene group, as described above. The alkylene and aryl group of an aralkyl may be substituted or unsubstituted. Examples include but are not limited to benzyl, 2-phenylalkyl, 3-phenylalkyl, and naphthylalkyl. In some embodiments, the alkylene is an unsubstituted straight chain containing 1, 2, 3, 4, 5, or 6 methylene unit(s).

As used herein, “heteroaralkyl” and “(heteroaryl)alkyl” refer to a heteroaryl group, as defined above, connected, as a substituent, via an alkylene group, as defined above. The alkylene and heteroaryl group of heteroaralkyl may be substituted or unsubstituted. Examples include but are not limited to 2-thienylalkyl, 3-thienylalkyl, furylalkyl, thienylalkyl, pyrrolylalkyl, pyridylalkyl, isoxazolylalkyl, and imidazolylalkyl, and their benzo-fused analogs. In some embodiments, the alkylene is an unsubstituted straight chain containing 1, 2, 3, 4, 5, or 6 methylene unit(s).

As used herein, “(heterocyclyl)alkyl” refer to a heterocyclic or a heterocyclyl group, as defined above, connected, as a substituent, via an alkylene group, as defined above. The alkylene and heterocyclyl groups of a (heterocyclyl)alkyl may be substituted or unsubstituted. Examples include but are not limited to (tetrahydro-2H-pyran-4-yl)methyl, (piperidin-4-yl)ethyl, (piperidin-4-yl)propyl, (tetrahydro-2H-thiopyran-4-yl)methyl, and (1,3-thiazinan-4-yl)methyl. In some embodiments, the alkylene is an unsubstituted straight chain containing 1, 2, 3, 4, 5, or 6 methylene unit(s).

As used herein, “cycloalkylalkyl” and “(cycloalkyl)alkyl” refer to a cycloalkyl group (as defined herein) connected, as a substituent, via an alkylene group. Examples include but are not limited to cyclopropylmethyl, cyclobutylmethyl, cyclopentylethyl, and cyclohexylpropyl. In some embodiments, the alkylene is an unsubstituted straight chain containing 1, 2, 3, 4, 5, or 6 methylene unit(s).

As used herein, “alkoxy” refers to the formula —OR wherein R is an alkyl group, as defined herein. A non-limiting list of alkoxy group includes methoxy, ethoxy, n-propoxy, 1-methylethoxy (isopropoxy), n-butoxy, iso-butoxy, sec-butoxy, and tert-butoxy. An alkoxy may be substituted or unsubstituted.

As used herein, “haloalkyl” refers to an alkyl group in which one or more of the hydrogen atoms are replaced by a halogen (e.g., mono-haloalkyl, di-haloalkyl, and tri-haloalkyl). Such groups include but are not limited to, chloromethyl, fluoromethyl, difluoromethyl, trifluoromethyl and 1-chloro-2-fluoromethyl, 2-fluoroisobutyl. A haloalkyl may be substituted or unsubstituted.

As used herein, “haloalkoxy” refers to an alkoxy group in which one or more of the hydrogen atoms are replaced by a halogen (e.g., mono-haloalkoxy, di-haloalkoxy and tri-haloalkoxy). Such groups include but are not limited to, chloromethoxy, fluoromethoxy, difluoromethoxy, trifluoromethoxy and 1-chloro-2-fluoromethoxy, 2-fluoroisobutoxy. A haloalkoxy may be substituted or unsubstituted.

As used herein, “amino” refer to a —NH₂ group. The term “mono-substituted amino group” as used herein refers to an amino (—NH₂) group where one of the hydrogen atom is replaced by a substituent. The term “di-substituted amino group” as used herein refers to an amino (—NH₂) group where each of the two hydrogen atoms is replaced by a substituent. The term “optionally substituted amino,” as used herein refer to a —NR_(A)R_(B) group where R_(A) and R_(B) are independently hydrogen, alkyl, cycloalkyl, aryl, heteroaryl, heterocyclyl, aralkyl, or heterocyclyl(alkyl), as defined herein.

As used herein, “alkylamino” or “(alkyl)amino” refers to a —NR_(A)R_(B) group where R_(A) and R_(B) are hydrogen or alkyl as defined above, and at least one of R_(A) and R_(B) is alkyl. The alkyl portion of the (alkyl)amine, includes, for example, C₁-C₆ alkyl groups.

As used herein, “aminoalkyl” or “(amino)alkyl” refers to an alkyl group in which one or more of the hydrogen atoms are replaced by an amino group or “—NR_(A)R_(B)” group as defined herein. The alkyl portion of the aminoalkyl, includes, for example, C₁-C₆ alkyl.

The term “halogen atom” or “halogen” as used herein, means any one of the radio-stable atoms of column 7 of the Periodic Table of the Elements, such as, fluorine, chlorine, bromine, and iodine.

As used herein, “alkoxyalkyl” or “(alkoxy)alkyl” refers to an alkoxy group connected via an alkylene group, such as C₂-C₈ alkoxyalkyl, or (C₁-C₆ alkoxy)C₁-C₆ alkyl, for example, —(CH₂)₁₋₃—OCH₃.

As used herein, “—O-alkoxyalkyl” or “—O-(alkoxy)alkyl” refers to an alkoxy group connected via an —O-(alkylene) group, such as —O—(C₁-C₆ alkoxy)C₁-C₆ alkyl, for example, —O—(CH₂)₁₋₃—OCH₃.

As used herein, “aryloxy” and “arylthio” refers to RO— and RS—, in which R is an aryl, as defined above, such as but not limited to phenyl. Both an aryloxy and arylthio may be substituted or unsubstituted.

A “sulfenyl” group refers to an “—SR” group in which R can be hydrogen, alkyl, alkenyl, alkynyl, carbocyclyl, aryl, heteroaryl, heterocyclyl, aralkyl, or heterocyclyl(alkyl), as defined above. A sulfenyl may be substituted or unsubstituted.

A “sulfinyl” group refers to an “—S(═O)—R” group in which R can be the same as defined with respect to sulfenyl. A sulfinyl may be substituted or unsubstituted.

A “sulfonyl” group refers to an “SO₂R” group in which R can be the same as defined with respect to sulfenyl. A sulfonyl may be substituted or unsubstituted.

An “O-carboxy” group refers to a “RC(═O)O—” group in which R can be hydrogen, alkyl, alkenyl, alkynyl, carbocyclyl, aryl, heteroaryl, heterocyclyl, aralkyl, or heterocyclyl(alkyl), as defined herein. An O-carboxy may be substituted or unsubstituted.

The terms “ester” and “C-carboxy” refer to a “—C(═O)OR” group in which R can be the same as defined with respect to O-carboxy. An ester or C-carboxy may be substituted or unsubstituted.

A “trihalomethanesulfonyl” group refers to an “X₃CSO₂—” group wherein X is a halogen.

A “trihalomethanesulfonamido” group refers to an “X₃CS(O)₂N(R)—” group wherein X is a halogen and R is hydrogen, alkyl, alkenyl, alkynyl, carbocyclyl, aryl, heteroaryl, heterocyclyl, aralkyl, or heterocyclyl(alkyl), as defined herein.

A “mercapto” group refers to an “—SH” group.

An “S-sulfonamido” group refers to a “—SO₂N(R_(A)R_(B))” group in which R_(A) and R_(B) can be independently hydrogen, alkyl, alkenyl, alkynyl, carbocyclyl, aryl, heteroaryl, heterocyclyl, aralkyl, or heterocyclyl(alkyl) as defined herein. An S-sulfonamido may be substituted or unsubstituted.

An “N-sulfonamido” group refers to a “RSO₂N(R_(A))—” group in which R and R_(A) can be independently hydrogen, alkyl, alkenyl, alkynyl, carbocyclyl, aryl, heteroaryl, heterocyclyl, aralkyl, or heterocyclyl(alkyl), as defined herein. An N-sulfonamido may be substituted or unsubstituted.

An “O-carbamyl” group refers to a “—OC(═O)N(R_(A)R_(B))” group in which R_(A) and R_(B) can be the same as defined with respect to S-sulfonamido. An O-carbamyl may be substituted or unsubstituted.

An “N-carbamyl” group refers to an “ROC(═O)N(R_(A))—” group in which R and R_(A) can be the same as defined with respect to N-sulfonamido. An N-carbamyl may be substituted or unsubstituted.

An “O-thiocarbamyl” group refers to a “—OC(═S)—N(R_(A)R_(B))” group in which R_(A) and R_(B) can be the same as defined with respect to S-sulfonamido. An O-thiocarbamyl may be substituted or unsubstituted.

An “N-thiocarbamyl” group refers to an “ROC(═S)N(R_(A))—” group in which R and R_(A) can be the same as defined with respect to N-sulfonamido. An N-thiocarbamyl may be substituted or unsubstituted.

A “C-amido” group refers to a “—C(═O)N(R_(A)R_(B))” group in which R_(A) and R_(B) can be the same as defined with respect to S-sulfonamido. A C-amido may be substituted or unsubstituted.

An “N-amido” group refers to a “RC(═O)N(R_(A))—” group in which R and R_(A) can be the same as defined with respect to N-sulfonamido. An N-amido may be substituted or unsubstituted.

Where the numbers of substituents is not specified (e.g., haloalkyl), there may be one or more substituents present. For example, “haloalkyl” may include one or more of the same or different halogens.

It is understood that, in any compound described herein having one or more chiral centers, if an absolute stereochemistry is not expressly indicated, then each center may independently be of R-configuration or S-configuration or a mixture thereof. Thus, the compounds provided herein may be enantiomerically pure, enantiomerically enriched, or may be stereoisomeric mixtures, and include all diastereomeric, and enantiomeric forms. In addition, it is understood that, in any compound described herein having one or more double bond(s) generating geometrical isomers that can be defined as E or Z, each double bond may independently be E or Z a mixture thereof. Stereoisomers are obtained, if desired, by methods such as, stereoselective synthesis and/or the separation of stereoisomers by chiral chromatographic columns. Likewise, it is understood that, in any compound described, all tautomeric forms are also intended to be included.

Wherever a substituent is depicted as a di-radical (i.e., has two points of attachment to the rest of the molecule), it is to be understood that the substituent can be attached in any directional configuration unless otherwise indicated. Thus, for example, a substituent depicted as -AE- or

includes the substituent being oriented such that the A is attached at the leftmost attachment point of the molecule as well as the case in which A is attached at the rightmost attachment point of the molecule. In addition, if a group or substituent is depicted as

L and when L is defined as a bond or absent; such group or substituent is equivalent to

It is to be understood that where compounds disclosed herein have unfilled valencies, then the valencies are to be filled with hydrogens and/or deuteriums.

It is understood that the compounds described herein can be labeled isotopically or by another other means, including, but not limited to, the use of chromophores or fluorescent moieties, bioluminescent labels, or chemiluminescent labels. Substitution with isotopes such as deuterium may afford certain therapeutic advantages from greater metabolic stability, such as, for example, increased in vivo half-life or reduced dosage requirements. Each chemical element as represented in a compound structure may include any isotope of said element. For example, in a compound structure a hydrogen atom may be explicitly disclosed or understood to be present in the compound. At any position of the compound that a hydrogen atom may be present, the hydrogen atom can be any isotope of hydrogen, including but not limited to hydrogen-1 (protium), hydrogen-2 (deuterium), and hydrogen-3 (tritium). Thus, reference herein to a compound encompasses all potential isotopic forms unless the context clearly dictates otherwise.

It is understood that the methods and formulations described herein include the use of crystalline forms, amorphous phases, and/or pharmaceutically acceptable salts, solvates, hydrates, and conformers of compounds of preferred embodiments, as well as metabolites and active metabolites of these compounds having the same type of activity. A conformer is a structure that is a conformational isomer. Conformational isomerism is the phenomenon of molecules with the same structural formula but different conformations (conformers) of atoms about a rotating bond. In specific embodiments, the compounds described herein exist in solvated forms with pharmaceutically acceptable solvents such as water, ethanol, or the like. In other embodiments, the compounds described herein exist in unsolvated form. Solvates contain either stoichiometric or non-stoichiometric amounts of a solvent, and may be formed during the process of crystallization with pharmaceutically acceptable solvents such as water, ethanol, or the like. Hydrates are formed when the solvent is water, or alcoholates are formed when the solvent is alcohol. In addition, the compounds provided herein can exist in unsolvated as well as solvated forms. In general, the solvated forms are considered equivalent to the unsolvated forms for the purposes of the compounds and methods provided herein. Other forms in which the compounds of preferred embodiments can be provided include amorphous forms, milled forms and nano-particulate forms.

Likewise, it is understood that the compounds described herein, such as compounds of preferred embodiments, include the compound in any of the forms described herein (e.g., pharmaceutically acceptable salts, crystalline forms, amorphous form, solvated forms, enantiomeric forms, tautomeric forms, and the like).

As used herein, the abbreviations for any protective groups, amino acids and other compounds, are, unless indicated otherwise, in accord with their common usage, recognized abbreviations, or the IUPAC-IUB Commission on Biochemical Nomenclature (See, Biochem. 11:942-944 (1972)).

The terms “protecting group” and “protecting groups” as used herein refer to any atom or group of atoms that is added to a molecule in order to prevent existing groups in the molecule from undergoing unwanted chemical reactions. Examples of protecting group moieties are described in T. W. Greene and P. G. M. Wuts, Protective Groups in Organic Synthesis, 3. Ed. John Wiley & Sons, 1999, and in J. F. W. McOmie, Protective Groups in Organic Chemistry Plenum Press, 1973, both of which are hereby incorporated by reference for the limited purpose of disclosing suitable protecting groups. The protecting group moiety may be chosen in such a way, that they are stable to certain reaction conditions and readily removed at a convenient stage using methodology known from the art. A non-limiting list of protecting groups include benzyl (Bn); substituted benzyl; alkylcarbonyls (e.g., t-butoxycarbonyl (BOC), acetyl (i.e., —C(═O)CH₃ or Ac), or isobutyryl (iBu); arylalkylcarbonyls (e.g., benzyloxycarbonyl (i.e., —C(═O)OCH₂Ph (Cbz)); arylcarbonyls (e.g., —C(═O)Ph (benzoyl or Bz)); substituted methyl ether (e.g., methoxymethyl ether (MOM)); substituted ethyl ether (e.g., methoxyethyl ether (MOE); a substituted benzyl ether; tetrahydropyranyl ether; silyl ethers (e.g., trimethylsilyl (TMS), triethylsilyl, triisopropylsilyl, t-butyldimethylsilyl (TBDMS), tri-iso-propylsilyloxymethyl (TOM), or t-butyldiphenylsilyl); esters (e.g., benzoate ester); carbonates (e.g., methoxymethylcarbonate); sulfonates (e.g., tosylate or mesylate); acyclic ketal (e.g., dimethyl acetal); cyclic ketals (e.g., 1,3-dioxane or 1,3-dioxolanes); acyclic acetal; cyclic acetal; acyclic hemiacetal; cyclic hemiacetal; cyclic dithioketals (e.g., 1,3-dithiane or 1,3-dithiolane); and triarylmethyl groups (e.g., trityl; monomethoxytrityl (MMTr); 4,4′-dimethoxytrityl (DMTr); or 4,4′,4″-trimethoxytrityl (TMTr)).

The term “leaving group” as used herein refers to any atom or moiety that is capable of being displaced by another atom or moiety in a chemical reaction. More specifically, in some embodiments, “leaving group” refers to the atom or moiety that is displaced in a nucleophilic substitution reaction. In some embodiments, “leaving groups” are any atoms or moieties that are conjugate bases of strong acids. Examples of suitable leaving groups include, but are not limited to, tosylates and halogens. Non-limiting characteristics and examples of leaving groups can be found, for example in Organic Chemistry, 2d ed., Francis Carey (1992), pages 328-331; Introduction to Organic Chemistry, 2d ed., Andrew Streitwieser and Clayton Heathcock (1981), pages 169-171; and Organic Chemistry, 5^(th) ed., John McMurry (2000), pages 398 and 408; all of which are incorporated herein by reference for the limited purpose of disclosing characteristics and examples of leaving groups.

The term “pharmaceutically acceptable salt” as used herein is a broad term, and is to be given its ordinary and customary meaning to a person of ordinary skill in the art (and is not to be limited to a special or customized meaning), and refers without limitation to a salt of a compound that does not cause significant irritation to an organism to which it is administered and does not abrogate the biological activity and properties of the compound. In some embodiments, the salt is an acid addition salt of the compound. Pharmaceutical salts can be obtained by reacting a compound with inorganic acids such as hydrohalic acid (e.g., hydrochloric acid or hydrobromic acid), sulfuric acid, nitric acid, and phosphoric acid. Pharmaceutical salts can also be obtained by reacting a compound with an organic acid such as aliphatic or aromatic carboxylic or sulfonic acids, for example formic acid, acetic acid (AcOH), propionic acid, glycolic acid, pyruvic acid, malonic acid, maleic acid, fumaric acid, trifluoroacetic acid (TFA), benzoic acid, cinnamic acid, mandelic acid, succinic acid, lactic acid, malic acid, tartaric acid, citric acid, ascorbic acid, nicotinic acid, methanesulfonic acid, ethanesulfonic acid, p-toluensulfonic acid, salicylic acid, stearic acid, muconic acid, butyric acid, phenylacetic acid, phenylbutyric acid, valproic acid, 1,2-ethanedisulfonic acid, 2-hydroxyethanesulfonic acid, benzenesulfonic acid, 2-naphthalenesulfonic acid, or naphthalenesulfonic acid. Pharmaceutical salts can also be obtained by reacting a compound with a base to form a salt such as an ammonium salt, an alkali metal salt, such as a lithium, sodium or a potassium salt, an alkaline earth metal salt, such as a calcium, magnesium or aluminum salt, a salt of organic bases such as dicyclohexylamine, N-methyl-D-glucamine, tris(hydroxymethyl)methylamine, (C₁-C₇ alkyl)amine, cyclohexylamine, dicyclohexylamine, triethanolamine, ethylenediamine, ethanolamine, diethanolamine, triethanolamine, tromethamine, and salts with amino acids such as arginine and lysine; or a salt of an inorganic base, such as aluminum hydroxide, calcium hydroxide, potassium hydroxide, sodium carbonate, sodium hydroxide, or the like. In some embodiments, the compounds described herein may be in the form of a trifluoroacetate salt.

As used herein, a “nucleotide” includes a nitrogen containing heterocyclic base, a sugar, and one or more phosphate groups. They are monomeric units of a nucleic acid sequence. In RNA, the sugar is a ribose, and in DNA a deoxyribose, i.e. a sugar lacking a hydroxyl group that is present in ribose. The nitrogen containing heterocyclic base can be purine or pyrimidine base. Purine bases include adenine (A) and guanine (G), and modified derivatives or analogs thereof, such as deazapurine. Pyrimidine bases include cytosine (C), thymine (T), and uracil (U), and modified derivatives or analogs thereof. The C-1 atom of deoxyribose is bonded to N-1 of a pyrimidine or N-9 of a purine.

As used herein, a “nucleoside” is structurally similar to a nucleotide, but is missing the phosphate moieties. An example of a nucleoside analogue would be one in which the label is linked to the base and there is no phosphate group attached to the sugar molecule. The term “nucleoside” is used herein in its ordinary sense as understood by those skilled in the art. Examples include, but are not limited to, a ribonucleoside comprising a ribose moiety and a deoxyribonucleoside comprising a deoxyribose moiety. A modified pentose moiety is a pentose moiety in which an oxygen atom has been replaced with a carbon and/or a carbon has been replaced with a sulfur or an oxygen atom. A “nucleoside” is a monomer that can have a substituted base and/or sugar moiety. Additionally, a nucleoside can be incorporated into larger DNA and/or RNA polymers and oligomers.

The term “purine base” is used herein in its ordinary sense as understood by those skilled in the art, and includes its tautomers. Similarly, the term “pyrimidine base” is used herein in its ordinary sense as understood by those skilled in the art, and includes its tautomers. A non-limiting list of optionally substituted purine-bases includes purine, deazapurine, 7-deazapurine, adenine, 7-deaza adenine, guanine, 7-deaza guanine, hypoxanthine, xanthine, alloxanthine, 7-alkylguanine (e.g. 7-methylguanine), theobromine, caffeine, uric acid and isoguanine. Examples of pyrimidine bases include, but are not limited to, cytosine, thymine, uracil, 5,6-dihydrouracil and 5-alkylcytosine (e.g., 5-methylcytosine).

As used herein, “derivative” or “analogue” means a synthetic nucleoside or nucleotide derivative having modified base moieties and/or modified sugar moieties. Such derivatives and analogs are discussed in, e.g., Scheit, Nucleotide Analogs (John Wiley & Son, 1980) and Uhlman et al., Chemical Reviews 90:543-584, 1990. Nucleotide analogs can also comprise modified phosphodiester linkages, including phosphorothioate, phosphorodithioate, alkyl-phosphonate, phosphoranilidate, phosphoramidite, and phosphoramidate linkages. “Derivative” and “analog” as used herein, may be used interchangeably, and are encompassed by the terms “nucleotide” and “nucleoside” defined herein.

As used herein, the term “phosphate” is used in its ordinary sense as understood by those skilled in the art, and includes its protonated forms (for example,

As used herein, the terms “monophosphate,” “diphosphate,” and “triphosphate” are used in their ordinary sense as understood by those skilled in the art, and include protonated forms.

Monovalent GalNAc Analogs of Formula (I)

Some embodiments provide a compound of Formula (I), or a pharmaceutically acceptable salt thereof as described herein:

-   -   wherein each of R¹, R², and R³ is independently hydrogen,         benzyl, or —C(═O)R⁸;     -   R⁴ is —C(═O)C₁₋₆ alkyl or —C(═O)C₁₋₆ haloalkyl;     -   R⁵ is a hydroxy protecting group;     -   R⁶ is hydrogen, a phosphoramidite moiety,         —C(═O)CH₂CH₂C(═O)R^(6A), or —P(OR^(6B))NR^(6C)R^(6D);     -   Y¹ is NR⁷, *NR⁷C(═O) or O, the asterisk * indicates that Y¹ is         connected to L³ through the nitrogen atom of Y¹, provided that         when Y¹ is *NR⁷C(═O), then L⁴ is absent;     -   Z¹ is C(R^(Z)), P(═S), P(═O) or N, wherein R^(Z) is hydrogen or         unsubstituted C₁₋₆ alkyl, provided that when Z¹ is N, both L⁴         and Y¹ are absent;     -   each of L¹, L², and L³ is independently a bond, —C(═O)—,         —C(═S)—, —S(═O)₂—, —C(═O)NR⁹—, —C(═S)NR⁹—, —C(═O)O—, —C(═S)O—,         —NR⁹C(═O)NR⁹—, —NR⁹C(═S)NR⁹—, —OP(═O)(OH)O—, —OP(═S)(OH)O—, —O—,         —S—, —NR⁹—, optionally substituted C₁₋₁₀ alkylene, optionally         substituted C₆₋₁₀ arylene, optionally substituted C₃₋₁₀         cycloalkylene, optionally substituted 5-10 membered         heteroarylene, optionally substituted 5 to 10 membered         heterocyclylene, or optionally substituted 2 to 15 membered         heteroalkylene wherein one or more carbon atoms are replaced         with C(═O), O, S or N, provided that at least one of L¹, L², and         L³ is not a bond;     -   L⁴ is optionally substituted C₁₋₈ alkylene;     -   each of R⁷ and R⁹ is independently hydrogen, unsubstituted C₁₋₆         alkyl, substituted C₁₋₆ alkyl, or an amino protecting group;     -   each R⁸ is independently C₁₋₆ alkyl, C₁₋₆ haloalkyl, or         optionally substituted phenyl;     -   R^(6A) is —OH, —OR¹⁰ or —NR¹¹R¹²;     -   each of R^(6B), R^(6C) and R^(6D) is independently H, C₁₋₆         haloalkyl, or unsubstituted or substituted C₁₋₆ alkyl;     -   R¹⁰ is unsubstituted or substituted C₁₋₆ alkyl, or a hydroxy         protecting group;     -   each of R¹¹ and R¹² is independently H, unsubstituted or         substituted C₁₋₆ alkyl, or an amino protecting group; and     -   each of m and n is independently 0, 1, 2 or 3, provided that     -   m and n cannot both be 0.

In some embodiments of Formula (I), when -L¹-L²-L³- comprise one or more C(═O), Y¹ is NR⁷, Z¹ is C(R^(Z)), and m+n=1; then R^(Z) is unsubstituted C₁₋₆ alkyl. In some embodiments of the compound of Formula (I), when -L¹-L²-L³- comprise one or more C(═O), Y¹ is NR⁷, and m+n=1; then Z¹ is P(═O), P(═S) or C(R^(Z)), where R^(Z) is unsubstituted C₁₋₆ alkyl.

In some embodiments of the compound of Formula (I), Y¹ is NH. In other embodiments, Y¹ is NR⁷, and R⁷ is methyl or an amino protecting group (e.g., —C(═O)OCH₂Ph or Cbz). In other embodiments, Y¹ is O. In some such embodiments, L⁴ is a straight chain unsubstituted C₁₋₆ alkylene, for example, C₁, C₂, C₃, C₄ or C₅ alkylene. In some embodiments, Z¹ is CH. In other embodiments, Z¹ is C(CH₃). In still other embodiments, Z¹ is P(═O).

In some embodiments of the compounds of Formula (I), Y¹ is *NR⁷C(═O) and the compound is also represented by Formula (Ia):

or a pharmaceutically acceptable salt thereof. In some embodiments, R⁷ is H. In another embodiment, R⁷ is methyl. In another embodiment, R⁷ is amino protecting group, e.g., a Cbz group. In one embodiment, R^(Z) is H. In other embodiments, R^(Z) is C₁₋₄ alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, or t-butyl.

In some embodiments of the compounds of Formula (I), Z¹ is N and L⁴ is absent, and the compound is also represented by Formula (Ib):

or a pharmaceutically acceptable salt thereof.

In some embodiments of the compounds of Formula (I), (Ia) or (Ib), each of R¹, R² and R³ is independently hydrogen, benzyl, or —C(═O)R⁸, wherein R⁸ is C₁₋₆ alkyl, C₁₋₆ haloalkyl, or optionally substituted phenyl. In some embodiments, R¹ is C(═O)CH₃. In some embodiments, R¹ is C(═O)Ph. In some embodiments, R² is C(═O)CH₃. In other embodiments, R² is C(═O)Ph. In some embodiments, R³ is C(═O)CH₃. In other embodiments, R³ is C(═O)Ph. In some embodiments, each of R¹, R² and R³ is C(═O)CH₃. In some other embodiments, each of R¹, R² and R³ is H. In some other embodiments, each of R¹, R² and R³ is C(═O)Ph. In some embodiments, R⁴ is —C(═O)C₁₋₆ alkyl. In other embodiments, R⁴ is —C(═O)C₁₋₆ haloalkyl. In one embodiment, R⁴ is —C(═O)CH₃. In another embodiment, R⁴ is —C(═O)CF₃.

In some embodiments of the compounds of Formula (I), (Ia) or (Ib), R⁵ is a trityl type hydroxy protecting group. In one embodiment, R⁵ is (4-methoxyphenyl)diphenylmethyl (i.e., monomethoxytrityl (MMTr)). In another embodiment, R⁵ is bis(4-methoxyphenyl)phenylmethyl (i.e., 4,4′-dimethoxytrityl (DMTr)). In yet another embodiment, R⁵ is tris(4-methoxyphenyl)methyl (i.e., 4,4′,4″-trimethoxytrityl (TMTr)). In further embodiments, R⁵ is 9-phenylxanthen-9-yl or 9-(4-methoxyphenyl)xanthen-9-yl.

In some embodiments of the compounds of Formula (I), (Ia) or (Ib), R⁶ is hydrogen. In other embodiments, R⁶ is a phosphoramidite moiety. In yet other embodiments, R⁶ is —C(═O)CH₂CH₂C(═O)R^(6A), wherein R^(6A) is —OH, —OR¹⁰ or —NR¹¹R¹². In some embodiments, each of R¹¹ and R¹² is independently H, optionally substituted C₁₋₆ alkyl, or an amino protecting group. In other embodiments, R⁶ is —P(OR^(6B))NR^(6C)R^(6D), wherein each of R^(6B), R^(6C) and R^(6D) is independently H, C₁₋₆ haloalkyl, or optionally substituted C₁₋₆ alkyl. In one embodiment, R⁶ is —C(═O)CH₂CH₂C(═O)OH. In another embodiment, R⁶ is

In some embodiments of the compounds of Formula (I), (Ia) or (Ib), each L¹, L², and L³ is independently a bond, —C(═O)—, —C(═S)—, —S(═O)₂—, —C(═O)NR⁹—, —C(═S)NR⁹—, —C(═O)O—, —C(═S)O—, —NR⁹C(═O)NR⁹—, —NR⁹C(═S)NR⁹—, —OP(═O)(OH)O—, —OP(═S)(OH)O—, —O—, —S—, —NR⁹—, optionally substituted C₁₋₁₀ alkylene, or optionally substituted 2 to 15 membered heteroalkylene wherein one or more carbon atoms (together with the hydrogen(s) attached to the carbon) are replaced with C(═O), O, S or N, provided that at least one of L¹, L², and L³ is not a bond. In some such embodiments, R⁹ is H, unsubstituted or substituted C₁₋₆ alkyl, for example, methyl or trifluoromethyl. In some further embodiments, L¹ is a bond, C₁₋₁₀ alkylene, or 2 to 15 membered heteroalkylene, wherein one or more carbon atoms (i.e., CH₂) are replaced with C(═O), O or N. In some embodiments, L¹ is a C₁₋₅ alkylene. In other embodiments, L¹ is 3 to 15 membered heteroalkylene comprising 1-5 units of PEG (i.e., L¹ is —(CH₂CH₂O)—₁₋₅). In some other embodiments, L¹ is 2 to 10 or 2 to 6 membered straight heteroalkylene where one, two or three carbon atoms is replaced by N or C(═O). In further embodiments, L¹ is a 2 to 6 membered heteroalkylene where one carbon is replaced by C(═O) or N. In some embodiments, L² is —C(═O)—, —C(═O)NR⁹—, —NR⁹—, or 2 to 15 membered heteroalkylene, wherein one or more carbon atoms are replaced with C(═O), O or N. In some such embodiments, R⁹ is H or methyl. In other embodiments, L² is 3 to 15 membered heteroalkylene comprising 1-5 units of PEG (i.e., L² is —(CH₂CH₂O)—₁₋₅). In some other embodiments, L² is 2 to 10 or 2 to 6 membered straight heteroalkylene where one, two or three carbon atoms is replaced by N or C(═O). In further embodiments, L² is a 2 to 6 membered heteroalkylene where one carbon is replaced by C(═O) or N. In some further embodiments, L³ is a bond, C₁₋₁₀ alkylene, or 2 to 15 membered heteroalkylene, wherein one or more carbon atoms are replaced with C(═O), O or N. In some embodiments, L³ is a C₁₋₅ alkylene. In other embodiments, L³ is 3 to 15 membered heteroalkylene comprising 1-5 units of PEG (i.e., L³ is —(CH₂CH₂O)—₁₋₅). In some other embodiments, L³ is 2 to 10 or 2 to 6 membered straight heteroalkylene where one, two or three carbon atoms is replaced by nitrogen or C(═O). In further embodiments, L³ is a 2 to 6 membered heteroalkylene where one carbon is replaced by C(═O) or N. In some embodiments, only L¹ is a bond. In some embodiments, only L² is a bond. In some embodiments, only L³ is a bond. In other embodiments, two of L¹, L² and L³ are each a bond. In other embodiments, at least one of L¹, L², and L³ is a ring or ring system including optionally substituted C₆₋₁₀ arylene (e.g., phenylene), optionally substituted C₃₋₁₀ cycloalkylene (e.g., C₃₋₇ cycloalkylene), optionally substituted 5-10 membered heteroarylene (e.g., 5 or 6 membered heteroarylene containing one, two or three heteroatoms selected from O, N or S), and optionally substituted 5 to 10 membered heterocyclylene (e.g., five or six membered heterocyclylene such as piperidylene, piperazinylene or morpholinylene). Non-limiting examples of -L¹-L²-L³- include: —(CH₂)₀₋₆C(═O)(CH₂)₀₋₆—, —(CH₂)₄C(═O)—, —(CH₂CH₂O)—₁₋₁₀, —(CH₂)₀₋₆—(CH₂CH₂O)₁₋₈—(CH₂)₀₋ ₆—, —(CH₂CH₂O)₂—(CH₂)₂—, —(CH₂CH₂O)₁₋₈(CH₂)₀₋₆C(═O)—, —(CH₂CH₂O)₂(CH₂)C(═O)—,

In some embodiments of the compounds of Formula (I), (Ia) or (Ib), m is 1 and n is 0. In other embodiments, m is 0 and n is 1. In other embodiments, both m and n are 1. In other embodiments, m is 1 and n is 2. In other embodiments, m is 2 and n is 1. In other embodiments, both m and n are 2. In other embodiments, both m and n are 3.

Further embodiments of the compounds of Formula (I) include:

and pharmaceutically acceptable salts thereof, wherein L¹, L² and L³ are defined herein, Ac is —C(O)CH₃. In some embodiments, R⁶ is —C(═O)CH₂CH₂C(═O)OH or

In some embodiments, R⁷ is H. In other embodiments, R⁷ is methyl or an amino protecting group (e.g., Cbz).

Additional non-limiting examples of the compounds of Formula (I) include:

or a pharmaceutically acceptable salt thereof.

Trivalent GalNAc Analogs of Formula (II)

Some embodiments provide a compound of Formula (II), or a pharmaceutically acceptable salt thereof as described herein:

or a pharmaceutically acceptable salt thereof, wherein

-   -   each of R^(1a), R^(1b), R^(1c), R^(2a), R^(2b), R^(2c), R^(3a),         R^(3b), and R^(3c) is independently hydrogen, benzyl, or         —C(═O)R⁸;     -   each of R^(4a), R^(4b) and R^(4c) is independently —C(═O)C₁₋₆         alkyl or —C(═O)C₁₋₆ haloalkyl;     -   R⁵ is a hydroxy protecting group;     -   R⁶ is hydrogen, a phosphoramidite moiety,         —C(═O)CH₂CH₂C(═O)R^(6A), or —P(OR^(6B))NR^(6C)R^(6D);     -   Y² is absent, NR⁷, *NR⁷C(═O) or O, the asterisk * indicates that         Y² is connected to L⁵ through the nitrogen atom of Y², provided         that when Y² is *NR⁷C(═O), then L⁴ is absent;     -   Z² is C(R^(Z)), P(═S), P(═O) or N, wherein R^(Z) is hydrogen or         unsubstituted C₁₋₆ alkyl, provided that when Z² is N, both L⁴         and Y² are absent;     -   each of X¹, X² and X³ is independently —O(CH₂)₁₋₃—,         —NH(CH₂)₁₋₃—, —C(═O)(CH₂)₁₋₃— or —NHC(═O)(CH₂)₁₋₃—;     -   each of L^(1a), L^(1b), L^(1c), L^(2a), L^(2b), L^(2c), L^(3a),         L^(3b), and L^(3c) is independently a bond, —C(═O)—, —C(═S)—,         —S(═O)₂—, —C(═O)NR⁹—, —C(═S)NR⁹—, —C(═O)O—, —C(═S)O—,         —NR⁹C(═O)NR⁹—, —NR⁹C(═S)NR⁹—, —OP(═O)(OH)O—, —OP(═S)(OH)O—, —O—,         —S—, —NR⁹—, optionally substituted C₁₋₁₀ alkylene, optionally         substituted C₆₋₁₀ arylene, optionally substituted C₃₋₁₀         cycloalkylene, optionally substituted 5-10 membered         hetetroarylene, optionally substituted 5 to 10 membered         heterocyclylene, or optionally substituted 2 to 15 membered         heteroalkylene wherein one or more carbon atoms are replaced         with C(═O), O, S or N, provided that at least one of L^(1a),         L^(1b) and L^(1c) is not a bond, at least one of L^(2a), L^(2b)         and L^(2c) is not a bond, and at least one of L^(3a), L^(3b) and         L^(3c) is not a bond;     -   L⁴ is optionally substituted C₁₋₈ alkylene or         —(CH₂)₁₋₃(OCH₂CH₂)₁₋₅OCH₂—;     -   L⁵ is absent, optionally substituted C₁₋₁₀ alkylene, or         optionally substituted 2 to 15 membered heteroalkylene wherein         one or more carbon atoms are replaced with C(═O), O, S or N;     -   each of R⁷ and R⁹ is independently hydrogen, unsubstituted C₁₋₆         alkyl, or substituted C₁₋₆ alkyl, or an amino protecting group;     -   each R⁸ is independently C₁₋₆ alkyl, C₁₋₆ haloalkyl, or         optionally substituted phenyl;     -   R^(6A) is —OH, —OR¹⁰ or —NR¹¹R¹²;     -   each of R^(6B), R^(6C) and R^(6D) is independently H, C₁₋₆         haloalkyl, or unsubstituted or substituted C₁₋₆ alkyl;     -   R¹⁰ is unsubstituted or substituted C₁₋₆ alkyl, or a hydroxy         protecting group;     -   each of R¹¹ and R¹² is independently H, unsubstituted or         substituted C₁₋₆ alkyl, or an amino protecting group;     -   each of m and n is independently 0, 1, 2 or 3, provided that m         and n cannot both be 0; and     -   k is 0 or 1.

In some embodiments of the compounds of Formula (II), when L⁵ is present and comprises one or more C(═O), Y² is NR⁷, Z¹ is C(R^(Z)), and m+n=1; then R^(Z) is unsubstituted C₁₋₆ alkyl. In some embodiments, when L⁵ is present and comprise one or more C(═O), Y² is NR⁷, and m+n=1; then Z² is P(═O), P(═S) or C(R^(Z)), where R^(Z) is unsubstituted C₁₋₆ alkyl.

In some embodiments of the compounds of Formula (II), k is 0, and the compound is also represented by Formula (IIa):

or a pharmaceutically acceptable salt thereof. In some embodiments of the compounds of Formula (II) or (IIa), Y² is NH. In other embodiments, Y² is O. In other embodiments, Y² is absent. In some such embodiments, L⁴ is a straight chain unsubstituted C₁₋₆ alkylene, for example, C₁, C₂, C₃, C₄ or C₅ alkylene. In some embodiments, L⁵ is 2 to 15 membered heteroalkylene where one or more carbon atoms are replaced with C(═O), O or N. In one such embodiment, L⁵ is —C(═O)CH₂CH₂C(═O)—. In another embodiment, L⁵ is —C(═O)CH₂CH₂CH₂CH₂C(═O)—. In other embodiments, L⁵ is absent. In some embodiments, Z² is CH. In other embodiments, Z² is C(CH₃). In still other embodiments, Z² is P(═O).

In some embodiments of the compounds of Formula (II), Y² is *NR⁷C(═O) and the compound is also represented by Formula (IIb):

or a pharmaceutically acceptable salt thereof. In some embodiments, R⁷ is H. In another embodiment, R⁷ is methyl. In another embodiment, R⁷ is an amino protecting group, e.g., a Cbz group. In one embodiment, R^(Z) is H. In other embodiments, R^(Z) is C₁₋₄ alkyl, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, or t-butyl. In some such embodiments, L⁵ is 2 to 15 membered heteroalkylene where one or more carbon atoms are replaced with C(═O), O or N. For example, L⁵ may comprise 3 to 15 membered heteroalkylene comprising 1-5 units of PEG (i.e., L⁵ is —(CH₂CH₂O)—₁₋₅). In further embodiments, L⁵ is 2 to 10 or 2 to 6 membered straight heteroalkylene where one or two carbon is replaced by C(═O). In one such embodiment, L⁵ is —C(═O)CH₂CH₂C(═O)—. In another such embodiment, L⁵ is —C(═O)CH₂CH₂CH₂CH₂C(═O)—. In other embodiments, L⁵ is C₁₋₁₀ alkylene.

In some embodiments of the compounds of Formula (II), Z² is N, and both Y² and L⁴ are absent, and the compound is also represented by Formula (IIc):

or a pharmaceutically acceptable salt thereof. In some embodiments, L⁵ is 2 to 15 membered heteroalkylene where one or more carbon atoms are replaced with C(═O), O or N. In one such embodiment, L⁵ is —C(═O)CH₂CH₂C(═O)—. In another embodiment, L⁵ is —C(═O)CH₂CH₂CH₂CH₂C(═O)—.

In some embodiments of the compounds of Formula (II), (IIa), (IIb) or (IIIc), each of R^(1a), R^(2a), R^(3a), R^(1b), R^(2b), R^(3b), R^(1c), R^(2c) and R^(3c) is independently hydrogen, benzyl, or —C(═O)R⁸, wherein R⁸ is C₁₋₆ alkyl, C₁₋₆ haloalkyl, or optionally substituted phenyl. In some embodiments, Ria is C(═O)CH₃. In some embodiments, R^(1a) is C(═O)Ph. In some embodiments, R^(2a) is C(═O)CH₃. In other embodiments, R^(2a) is C(═O)Ph. In some embodiments, R^(3a) is C(═O)CH₃. In other embodiments, R^(3a) is C(═O)Ph. In some embodiments, each of R^(1a), R^(2a) and R^(3a) is C(═O)CH₃. In some other embodiments, each of R^(1a), R^(2a) and R^(3a) is H. In some other embodiments, each of R^(1a), R^(2a) and R^(3a) is C(═O)Ph. In some embodiments, R^(4a) is —C(═O)C₁₋₆ alkyl. In other embodiments, R^(4a) is —C(═O)C₁₋₆ haloalkyl. In one embodiment, R^(4a) is —C(═O)CH₃. In another embodiment, R^(4a) is —C(═O)CF₃. In some embodiments, R^(1b) is C(═O)CH₃. In some embodiments, R^(1b) is C(═O)Ph. In some embodiments, R^(2b) is C(═O)CH₃. In other embodiments, R^(2b) is C(═O)Ph. In some embodiments, R^(3b) is C(═O)CH₃. In other embodiments, R^(3b) is C(═O)Ph. In some embodiments, each of R^(1b), R^(2b) and R^(3b) is C(═O)CH₃. In some other embodiments, each of R^(1b), R^(2b) and R^(3b) is H. In some other embodiments, each of R^(1b), R^(2b) and R^(3b) is C(═O)Ph. In some embodiments, R^(4b) is —C(═O)C₁₋₆ alkyl. In other embodiments, R^(4b) is —C(═O)C₁₋₆ haloalkyl. In one embodiment, R^(4b) is —C(═O)CH₃. In another embodiment, R^(4b) is —C(═O)CF₃. In some embodiments, R^(1c) is C(═O)CH₃. In some embodiments, R^(1c) is C(═O)Ph. In some embodiments, R^(2c) is C(═O)CH₃. In other embodiments, R^(2c) is C(═O)Ph. In some embodiments, R^(3c) is C(═O)CH₃. In other embodiments, R^(3c) is C(═O)Ph. In some embodiments, each of R^(1c), R^(2c) and R^(3c) is C(═O)CH₃. In some other embodiments, each of R^(1c), R^(2c) and R^(3c) is H. In some other embodiments, each of R^(1c), R^(2c) and R^(3c) is C(═O)Ph. In some embodiments, R^(4c) is —C(═O)C₁₋₆ alkyl. In other embodiments, R^(4c) is —C(═O)C₁₋₆ haloalkyl. In one embodiment, R^(4c) is —C(═O)CH₃. In another embodiment, R^(4c) is —C(═O)CF₃.

In some embodiments of the compounds of Formula (II), (IIa), (IIb) or (IIIc), R⁵ is a trityl type hydroxy protecting group. In one embodiment, R⁵ is (4-methoxyphenyl)diphenylmethyl (i.e., monomethoxytrityl (MMTr)). In another embodiment, R⁵ is bis(4-methoxyphenyl)phenylmethyl (i.e., 4,4′-dimethoxytrityl (DMTr)). In yet another embodiment, R⁵ is tris(4-methoxyphenyl)methyl (i.e., 4,4′,4″-trimethoxytrityl (TMTr)). In further embodiments, R⁵ is 9-phenylxanthen-9-yl or 9-(4-methoxyphenyl)xanthen-9-yl.

In some embodiments of the compounds of Formula (II), (IIa), (IIb) or (IIIc), R⁶ is hydrogen. In other embodiments, R⁶ is a phosphoramidite moiety. In yet other embodiments, R⁶ is —C(═O)CH₂CH₂C(═O)R^(6A), wherein R^(6A) is —OH, —OR¹⁰ or —NR¹¹R¹². In some embodiments, each of R¹¹ and R¹² is independently H, optionally substituted C₁₋₆ alkyl, or an amino protecting group. In other embodiments, R⁶ is —P(OR^(6B))NR^(6C)R^(6D), wherein each of R^(6B), R^(6C) and R^(6D) is independently H, C₁₋₆ haloalkyl, or optionally substituted C₁₋₆ alkyl. In one embodiment, R⁶ is —C(═O)CH₂CH₂C(═O)OH. In another embodiment, R⁶ is

In some embodiments of the compounds of Formula (II), (IIa), (IIb) or (IIIc), each of X¹ and X³ is —C(═O)CH₂CH₂—, and X² is —C(═O)CH₂—. In other embodiments, each of X¹, X² and X³ is —OCH₂—. In still other embodiments, each of X¹, X² and X³ is —NHCH₂—. In some other embodiments, each of X¹, X² and X³ is —NHC(═O)CH₂CH₂—. In some other embodiments, X¹ and X³ are each —NHC(═O)CH₂CH₂— and X² is —NHC(═O)CH₂—.

In some embodiments of the compounds of Formula (II), (IIa), (IIb) or (IIIc), each L^(1a), L^(1b), L^(1c), L^(2a), L^(2b), L^(2c), L^(3a), L^(3b), and L^(3c) is independently a bond, —C(═O)—, —C(═S)—, —S(═O)₂—, —C(═O)NR⁹—, —C(═S)NR⁹—, —C(═O)O—, —C(═S)O—, —NR⁹C(═O)NR⁹—, —NR⁹C(═S)NR⁹—, —OP(═O)(OH)O—, —OP(═S)(OH)O—, —O—, —S—, —NR⁹—, optionally substituted C₁₋₁₀ alkylene, or optionally substituted 2 to 15 membered heteroalkylene wherein one or more carbon atoms (together with the hydrogen(s) attached to the carbon) are replaced with C(═O), O, S or N, provided that at least one of L^(1a), L^(1b) and L^(1c) is not a bond, at least one of L^(2a), L^(2b) and L^(2c) is not a bond, and at least one of L^(3a), L^(3b) and L^(3c) is not a bond. In some such embodiments, R⁹ is H, unsubstituted or substituted C₁₋₆ alkyl, for example, methyl or trifluoromethyl. In some further embodiments, each of L^(1a), L^(1b) and L^(1c) is independently a bond, C₁₋₁₀ alkylene, or 2 to 15 membered heteroalkylene, wherein one or more carbon atoms (i.e., CH₂) are replaced with C(═O), O or N. In some embodiments, each of L^(1a), L^(1b) and L^(1c) is independently a C₁₋₅ alkylene. In other embodiments, each of L^(1a), L^(1b) and L^(1c) is independently 3 to 15 membered heteroalkylene comprising 1-5 units of PEG (i.e., each of L^(1a), L^(1b) and L^(1c) is independently —(CH₂CH₂O)—₁₋₅). In some other embodiments, each of L^(1a), L^(1b) and L^(1c) is independently 2 to 10 or 2 to 6 membered straight heteroalkylene where one, two or three carbon atoms is replaced by N or C(═O). In further embodiments, each of L^(1a), L^(1b) and L^(1c) is independently a 2 to 6 membered heteroalkylene where one carbon is replaced by C(═O) or N. In some embodiments, each of L^(2a), L^(2b) and L^(2c) is independently —C(═O)—, —C(═O)NR⁹—, —NR⁹—, or 2 to 15 membered heteroalkylene, wherein one or more carbon atoms are replaced with C(═O), O or N. In some such embodiments, R⁹ is H or methyl. In other embodiments, each of L^(2a), L^(2b) and L^(2c) is independently 3 to 15 membered heteroalkylene comprising 1-5 units of PEG (i.e., each of L^(2a), L^(2b) and L^(2c) is independently —(CH₂CH₂O)—₁₋₅). In some other embodiments, each of L^(2a), L^(2b) and L^(2c) is independently 2 to 10 or 2 to 6 membered straight heteroalkylene where one, two or three carbon atoms is replaced by N or C(═O). In further embodiments, each of L^(2a), L^(2b) and L^(2c) is independently a 2 to 6 membered heteroalkylene where one carbon is replaced by C(═O) or N. In some further embodiments, each of L^(3a), L^(3b) and L^(3c) is independently a bond, C₁₋₁₀ alkylene, or 2 to 15 membered heteroalkylene, wherein one or more carbon atoms are replaced with C(═O), O or N. In some embodiments, each of L^(3a), L^(3b) and L^(3c) is independently a C₁₋₅ alkylene. In other embodiments, each of L^(3a), L^(3b) and L^(3c) is independently 3 to 15 membered heteroalkylene comprising 1-5 units of PEG (i.e., each of L^(3a), L^(3b) and L^(3c) is independently —(CH₂CH₂O)—₁₋₅). In some other embodiments, each of L^(3a), L^(3b) and L^(3c) is independently 2 to 10 or 2 to 6 membered straight heteroalkylene where one, two or three carbon atoms is replaced by nitrogen or C(═O). In further embodiments, each of L^(3a), L^(3b) and L^(3c) is independently a 2 to 6 membered heteroalkylene where one carbon is replaced by C(═O) or N. In some embodiments, only L¹ is a bond. In some embodiments, only L^(2a), L^(2b) and L^(2c) are a bond. In some embodiments, only L^(3a), L^(3b) and L^(3c) are a bond. In other embodiments, two of Lia, L²a and L³a are each a bond. In other embodiments, two of L^(1b), L^(2b) and L^(3b) are each a bond. In other embodiments, two of L^(1c), L^(2c) and L^(3c) are each a bond. In other embodiments, at least one of L^(1a), L²a and L^(3a), one of L^(1b), L^(2b) and L^(3b), and/or one of L^(1c), L^(2c) and L^(3c) is a ring or ring system including optionally substituted C₆₋₁₀ arylene (e.g., phenylene), optionally substituted C₃₋₁₀ cycloalkylene (e.g., C₃₋₇ cycloalkylene), optionally substituted 5-10 membered heteroarylene (e.g., 5 or 6 membered heteroarylene containing one, two or three heteroatoms selected from O, N or S), and optionally substituted 5 to 10 membered heterocyclylene (e.g., five or six membered heterocyclylene such as piperidylene, piperazinylene or morpholinylene). Non-limiting examples of -L^(1a)-L^(2a)-L^(3a)-, -L^(1b)-L^(2b)-L^(3b)- or -L^(1c)-L^(2c)-L^(3c)- include: —(CH₂CH₂O)₁₋₁₀—, —(CH₂CH₂O)₃—, —(CH₂)₀₋₆—(CH₂CH₂O)₁₋₈—(CH₂)₀₋₆—,

In some embodiments of the compounds of Formula (II), (IIa), (IIb) or (IIIc), m is 1 and n is 0. In other embodiments, m is 0 and n is 1. In other embodiments, both m and n are 1. In other embodiments, both m and n are 2. In other embodiments, both m and n are 3.

Further embodiments of the compounds of Formula (II) has the Formula (IId):

or a pharmaceutically acceptable salt thereof, wherein

-   -   each of X¹, X² and X³ is —OCH₂— or —NHCH₂—, or each of X¹ and X³         is —C(═O)CH₂CH₂—, and X² is —C(═O)CH₂—, or each of X¹ and X³ is         —NHC(═O)CH₂CH₂—, and X² is —NHC(═O)CH₂—;     -   L⁵, -L^(1a)-L^(2a)-L^(3a)-, -L^(1b)-L^(2b)-L^(3b)- and         -L^(1c)-L^(2c)-L^(3c)- are defined herein (for example, as         described in connection with Formula (IIa), (IIb) or (IIc));     -   Y² is NH, *NH(C═O), O or absent;

In some embodiments, R⁶ is —C(═O)CH₂CH₂C(═O)OH. In some other embodiments, R⁶ is

Additional non-limiting examples of the compounds of Formula (II) include:

or a pharmaceutically acceptable salt thereof.

In any embodiments of the compounds described herein, when R⁶ comprises a succinate moiety (—C(O)CH₂CH₂C(O)OH), the compound may be attached to a solid support through the succinate moiety, optionally via a linker.

In any embodiments of the compounds described herein, when R⁶ comprises a phosphoramidite moiety such as

the compound may be used to react with 5′-OH of an oligo. Solid Support Conjugated with GalNAc Compounds

Some embodiments of the present application relate to a solid support comprising the compound of Formula (I) (including (Ia) and (Ib)), Formula (II) (including (IIa) through (IId)) as described herein covalently attached thereto, for example, via R⁶ of the compound. In one embodiment, R⁶ is —C(═O)CH₂CH₂C(═O)OH. In further embodiments, the compound is covalently attached to the solid support via a moiety

wherein the dashed line refers to the connection with the solid support, optionally through an additional linker, and the squiggly line refers to the point of the attachment of the oxygen atom (that is covalently attached to R⁶ of the compound) to the remaining portion of the compound. In further embodiments, the solid support comprises an oligonucleotide, and the compound is incorporated into the oligonucleotide sequence, for example, to the terminal of the oligo sequence (either at the 5′ end or at the 3′ end), through —OR⁵ functionality of the compound after R⁵ is deprotected to expose the free hydroxy group. In any embodiments, the solid support may comprise controlled pore glass (CPG) or macroporous polystyrene (MPPS).

Functionalized GalNAc Analogs in Oligonucleotide Synthesis

Some embodiments of the present application relate to a method for preparing a synthetic oligonucleotide, comprising reacting a compound described herein, with an oligonucleotide. In some embodiments, the oligonucleotide comprises 1 to 100 base length, 5 to 50 base length, or 10 to 30 base length. In further embodiments, the reaction is conducted on a solid support.

Step 1: De-Blocking (Detritylation)

The DMTr group is removed with a solution of an acid, such as 2% trichloroacetic acid (TCA) or 3% dichloroacetic acid (DCA), in an inert solvent (dichloromethane or toluene). The orange-colored DMTr cation formed is washed out; the step results in the solid support-bound oligonucleotide precursor bearing a free 5′-terminal hydroxyl group.

Step 2: Coupling

A 0.02-0.2M solution of nucleoside phosphoramidite (or a mixture of several phosphoramidites) in acetonitrile is activated by a 0.2-0.7 M solution of an acidic azole catalyst, 1H-tetrazole, 5-ethylthio-1H-tetrazole, 2-benzylthiotetrazole, 4,5-dicyanoimidazole, or a number of similar compounds. The mixing is usually very brief and occurs in fluid lines of oligonucleotide synthesizers (see below) while the components are being delivered to the reactors containing solid support. The activated phosphoramidite in 1.5-20-fold excess over the support-bound material is then brought in contact with the starting solid support (first coupling) or a support-bound oligonucleotide precursor (following couplings) whose 5′-hydroxy group reacts with the activated phosphoramidite moiety of the incoming nucleoside phosphoramidite to form a phosphite triester linkage. The reaction is also highly sensitive to the presence of water, particularly when dilute solutions of phosphoramidites are used, and is commonly carried out in anhydrous acetonitrile. Upon the completion of the coupling, any unbound reagents and by-products are removed by washing.

Step 3: Capping

The capping step is performed by treating the solid support-bound material with a mixture of acetic anhydride and 1-methylimidazole or, less often, DMAP as catalysts and, in the phosphoramidite method, serves two purposes. After the completion of the coupling reaction, a small percentage of the solid support-bound 5′-OH groups (0.1 to 1%) remains unreacted and needs to be permanently blocked from further chain elongation to prevent the formation of oligonucleotides with an internal base deletion commonly referred to as (n-1) shortmers. The unreacted 5′-hydroxy groups are, to a large extent, acetylated by the capping mixture. It has also been reported that phosphoramidites activated with ¹H-tetrazole react, to a small extent, with the O⁶ position of guanosine. Upon oxidation with I₂/water, this side product, possibly via O⁶—N7 migration, undergoes depurination. The apurinic sites thus formed are readily cleaved in the course of the final deprotection of the oligonucleotide under the basic conditions to give two shorter oligonucleotides thus reducing the yield of the full-length product. The O⁶ modifications are rapidly removed by treatment with the capping reagent as long as the capping step is performed prior to oxidation with I₂/water.

Step 4: Oxidation

The newly formed tricoordinated phosphite triester linkage is not natural and is of limited stability under the conditions of oligonucleotide synthesis. The treatment of the support-bound material with iodine and water in the presence of a weak base (pyridine, lutidine, or collidine) oxidizes the phosphite triester into a tetracoordinated phosphate triester, a protected precursor of the naturally occurring phosphate diester internucleosidic linkage. Oxidation may be carried out under anhydrous conditions using tert-Butyl hydroperoxide or (1S)-(+)-(10-camphorsulfonyl)-oxaziridine (CSO). The step of oxidation may be substituted with a sulfurization step to obtain oligonucleotide phosphorothioates. In the latter case, the sulfurization step is best carried out prior to capping.

In solid-phase synthesis, an oligonucleotide being assembled is covalently bound, via its 3′-terminal hydroxy group, to a solid support material and remains attached to it over the entire course of the chain assembly. The solid support is contained in columns whose dimensions depend on the scale of synthesis and may vary between 0.05 mL and several liters. At the end of the chain assembly, the oligonucleotide is released from the solid support and is eluted from the column or the well. The two most often used solid-phase materials are controlled pore glass (CPG) and macroporous polystyrene (MPPS).

In contrast to organic solid-phase synthesis and peptide synthesis, the synthesis of oligonucleotides proceeds best on non-swellable or low-swellable solid supports. The two most often used solid-phase materials are controlled pore glass (CPG) and macroporous polystyrene (MPPS).

CPG is commonly defined by its pore size. In oligonucleotide chemistry, pore sizes of 500, 1000, 1500, 2000, and 3000 Å are used to allow the preparation of about 50, 80, 100, 150, and 200-mer oligonucleotides, respectively. To make native CPG suitable for further processing, the surface of the material is treated with (3-aminopropyl)triethoxysilane to give aminopropyl CPG. The aminopropyl arm may be further extended to result in long chain aminoalkyl (LCAA) CPG. The amino group is then used as an anchoring point for linkers suitable for oligonucleotide synthesis.

MPPS suitable for oligonucleotide synthesis is a low-swellable, highly cross-linked polystyrene obtained by polymerization of divinylbenzene, styrene, and 4-chloromethylstyrene in the presence of a porogeneous agent. The macroporous chloromethyl MPPS obtained is converted to aminomethyl MPPS.

EXAMPLES

Some aspects of the embodiments discussed above are disclosed in further detail in the following examples, which are not in any way intended to limit the scope of the present disclosure. Those in the art will appreciate that many other embodiments also fall within the scope of the compositions, kits and methods of the present application, as is described herein above and in the claims.

Example 1. General Procedure for the Preparation of Monovalent GalNAc Analogs

Step 1: GalNAc (10 g, 25.7 mmol) and Compound 1 (15.4 g, 102.7 mmol) were dissolved in DCM (100 mL) and CF₃SO₃H (0.34 mL, 3.85 mmol) was then added. The reaction mixture was reflux under argon overnight and then cooled down to rt. This mixture was then poured into 1 M NaHCO₃ (51 mL), and the organic layer was separated, washed with water, brine and dried over Na_(s)SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using hexanes/ethyl acetate (1/1) to DCM/MeOH (2% to 8% MeOH). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 2 in quantitative yields. MS: found: [M+H]=505.7; calc: [M+H]=505.2.

Step 2: Compound 2 (0.224 g, 0.44 mmol) was in THF (3 mL) and Pd/C (22 mg, 10 wt %) was added. The reaction mixture was flushed with H₂ for one minute and the flask was sealed with septum. A balloon filled with hydrogen was inserted to the flask, and it was allowed to stir at rt for 3 h and filtered through celite pad. The pad was washed with ethyl acetate and the combined organic phase was concentrated to dryness under vacuum to Compound 3 in quantitative yields. MS: found: [M+H]=479.6; calc: [M+H]=479.2. Compound 3 was used without further purification.

Step 3. Compound 3 (0.44 mmol) from above was dissolved in DMF (2.2 mL) and DIEA (0.77 mL, 4.4 mmol) was then added. The mixture was stirred under argon until dissolved. Compound 4 (0.19 g, 0.44 mmol) was added followed by HBTU (0.19 g, 0.49 mmol). The reaction mixture was stirred at r.t overnight and was diluted with EtOAc (20 mL). This mixture was extracted with saturated NaHCO₃ (20 mL), brine (20 mL), and the organic phase was dried over Na₂SO₄. After filtration the solution was concentrated to dryness to afford crude Compound 5. MS: found [M−H]=895.9; calc: [M−H]=895.4.

Compound 6 is prepared from compound 5 by reacting it with succinic anhydride.

Example 2. General Procedure for the Preparation of Trivalent GalNAc Analogs

Compound 7: GalNAc (10 g, 25.7 mmol) and triethylene glycol (14 mL, 102.7 mmol) were dissolved in DCM (100 mL) and CF₃SO₃H (0.34 mL, 3.85 mmol) was then added. The reaction mixture was stirred at 60° C. overnight. The mixture was cooled down to r.t. and then poured into 1 M NaHCO₃ (51 mL). The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration, the organic layer was concentrated to dryness under vacuum, and the crude product was used without further purification. LCMS: found: [M+H]=480.6; calc: [M+H]=480.2.

Compounds 9, 10, and 11a/11b can be prepared following similar procedures described in Example 1.

Example 3. Preparation of Monovalent GalNAc Analogs Compounds 15 and 17

Compound 14: GalNAc-pentanoic acid (12) (1 g, 2.23 mmol), compound 13 (1.1 g, 2.45 mmol), HATU (1 g, 2.68 mmol) and TEA (677 mg, 6.69 mmol) were dissolved in THF. The mixture was allowed to stir at room temperature and monitored by TLC. THF was removed and then the mixture was redissolved in DCM and washed with water. The organic layer was separated and dried over sodium sulfate, filtered, and concentrated. The crude was subjected to flash column chromatography using DCM to MeOH/DCM=10%, to afford Compound 14 (1.7 g, 87%) as a white solid. MS: found: [M+H]=879.9; calc: [M+H]=879.4.

Compound 15: To a solution of compound 14 (1.7 g, 1.9 mmol) and TEA (404 mg, 4.0 mmol) in DCM (15 mL), was added 3-((chloro(diisopropylamino)phosphanyl)oxy)propanenitrile (474 mg, 3.0 mmol). The reaction was monitored by TLC. Upon completion, the reaction was quenched by 20 ml saturate sodium bicarbonate, and washed with 3×20 mL saturate sodium bicarbonate and 20 ml brine. The organic layer was dried over sodium sulfate, filtered, and concentrated. The residual was redissolved in 20 ml acetonitrile, and washed with 3×20 mL hexane. The acetonitrile layer was concentrated and subjected to flash column chromatography using DCM to triethylamine (TEA)/DCM=6% to afford Compound 15 (1.1 g, 54%) as a white solid. MS: found: [M+H]=1079.0; calc: [M+H]=1079.5. ³¹PNMR (mixture of diastereomers, DMSO-d₆): δ 146.373, 146.205.

Compound 16: To a solution of Compound 14 (95 mg, 0.11 mmol) and TEA (75 uL, 0.54 mmol) in DCM (1 ml), was added succinic anhydride (16 mg, 0.16 mmol). The reaction was monitored by TLC. The mixture was washed with water, dried over sodium sulfate, and evaporated to form a crude which is used directly for next step. MS: found: [M−H]=978.1; calc: [M−H]=977.4.

Compound 17: To a solution of compound 16 (1.27 g, 1.3 mmol) in anhydrous acetonitrile (100 mL) was added TBTU (501 mg, 1.56 mmol) and TEA (0.45 mL, 3.25 mmol). The mixture was stirred at rt for 10 min. Pretreated LCAA CPG 500A (20 g, loading: 152 μmol/g) was added. The resulting mixture was slowly agitated at 25° C. for 3 hrs. The mixture was then filtered, the CPG was washed with acetonitrile (50 mL×3) and THF (50 mL×3) successively. The CPG was dried under reduced pressure for 3 hrs. Loading was determined by standard DMTr assay by UV-Vis (498 nm) to be 54 μmol/g before capping.

To the CPG was added a mixture of Ac₂O (4 mL), N-methylimidazole (4 mL) and pyridine (4 mL) in anhydrous THF. The resulting mixture was slowly agitated at 25° C. for 1 hr. The mixture was filtered. The CPG was washed with THF (50 mL×3), 10% pyridine in EtOH (50 mL×3), EtOH (50 mL×3), acetonitrile (50 mL×3) and MTBE (50 mL×3) successively. The CPG was dried under reduced pressure overnight to give compound 17 (21 g, Loading was determined by standard DMTr assay by UV-Vis (498 nm) to be 51 μmol/g). Ninhydrin test: negative.

Example 4. Preparation of Trivalent GalNAc Analogs Compounds 24 and 25

Compound 18: Step 1: Tris[[2-(tert-butoxycarbonyl)ethoxy]methyl]methylamine (0.30 g 0.593 mmol) was dissolved in DCM and a solution of 25% Na₂CO₃ in water was added with vigorous stirring. CbzCl (0.75 mL, 1.78 mmol) was added. The reaction mixture was stirred at room temperature overnight and was monitored by TLC. Upon completion DCM (10 mL) and water (10 mL) were added to the reaction mixture. Organic phase was separated, and the aqueous phase was then extracted with DCM (2×10 mL). Combined organic phase was dried over Na₂SO₄, filtered, and concentrated to dryness. This material was used without further purification. MS: found: [M+H]=640.5; calc: [M+H]=640.4. Step 2: The above material was dissolved in 25% TFA in DCM (5.0 mL), and the reaction mixture was stirred at room temperature overnight. After evaporation, the oil was co-evaporated with toluene (3×5 mL) and dried under high vacuum for 5 h to obtain Compound 18 as pale-yellow oil (0.32 g, 114%, contain TFA residual). Compound 18 was used without further purification. MS: found: [M+Na]=494.4; calc: [M+Na]=494.5.

Compound 20: Compound 18 (1.64 g, 3.48 mmol) was dissolved in DCE (37 mL), and TEA (2.2 mL) was added followed by HATU (5.29 g, 13.9 mmol). This solution was allowed to stir at room temperature for 1 h. A solution of Compound 19 in DCE (37 mL) and TEA (2.2 mL) was added to the activated acid solution. This reaction mixture was stirred at room temperature overnight. Water (100 mL) was added to the reaction mixture with vigorous stirring. The organic phase was separated, and the aqueous phase was extracted with DCM (2×50 mL). The combined organic phase was then washed with a solution of 10% citric acid and 10% NaCl (2×50 mL), dried over Na₂SO₄, filtered, and concentrated to dryness. The crude material was purified by flash column chromatograph eluted with DCM and MeOH (0% to 15% MeOH) to afford Compound 20 as pale-yellow foam (2.64 g, 38.2%). MS: found: [M+H]=1985.3; calc: [M+H]=1984.9.

Compound 21: Compound 20 (2.64 g, 1.33 mmol) was dissolved in a mixture of MeOH (13 mL) and TFA (0.10 mL). Pd/C (0.264 g, 10 wt %) was added under argon purge. The reaction was purged with H₂ was sealed with septum. The reaction was then stirred at room temperature overnight. Upon completion the reaction the mixture was filtered through a celite pad, and the pad was washed with MeOH (3×10 mL). The filtrate was concentrated to dryness to afford Compound 21 (2.40 g, 92%) as pale-yellow foam. This material was used without further purification. MS: found: [M+H]=1851.6; calc: [M+H]=1851.9.

Compound 22 was synthesized according to the methods described in International Patent Publication No. WO 2017/177326, which is incorporated by reference herein in its entirety.

Compound 23: Compound 22 (0.100 g, 0.154 mmol) was dissolved in a mixture of DCE (0.8 mL) and TEA (86 μL), and HATU (70.3 mg, 0.185 mmol) was added. Compound 21 (0.302 g, 0.154 mmol) was then added to the mixture, and the reaction mixture was stirred at room temperature overnight. Upon completion the reaction mixture was diluted with DCM (10 mL), a solution of 5% NaHCO₃ (10 mL) was added with vigorous stirring. The organic phase was separated, and the aqueous phase was extracted with DCM (2×10 mL). The combined organic phase was dried over Na₂SO₄, filtered, and concentrated to dryness. The crude material was purified by flash column chromatograph eluted with DCM with 2% TEA and MeOH (0% to 10% MeOH) to afford Compound 23 as pale-yellow foam (0.32 g, 86.5%). MS: found: [M+2H/2+Na]²⁺=1214.7; calc: [M+2H/2+Na]²⁺=1214.6.

Compound 24: Compound 23 (100 mg, 0.043 mmol) and triethyl amine (6.5 mg, 0.065 mmol) was dissolved in 2 ml DCM, followed by the addition of succinic anhydride (6.5 mg, 0.065 mmol). The reaction was monitored by TLC. Upon completion, the mixture was concentrated and the crude was directly used for next step. Rf=0.1-0.3 in TEA/MeOH/DCM=0.5/10/90. The above crude product, 1000 Å LCAA CPG (0.30 g), TBTU (18 mg, 1.3 eq.), TEA (13 mg, 3 eq.) were dispersed in acetonitrile (1.5 mL). The mixture was placed on a rotovap and stirred for 2 hours at 25° C. The mixture was filtered. The CPG was washed with acetonitrile (3×3 mL), THF (3×3 mL), and MTBE (3×3 mL), and dried to afford uncapped CPG. The uncapped CPG was then dispersed in THF (1.5 mL) with acetic anhydride (0.06 mL), pyridine (0.06 mL) and N-methylimidazole (NMI) (0.06 mL). The mixture was placed on a rotovap and stirred for 1 h at 25° C. The mixture was then filtered, and the CPG was washed with pyridine/10% ethanol (3×3 mL), ethanol (3×3 mL), MeCN (3×3 mL), THF (3×3 mL), and MTBE (3×3 mL), and dried to afford desired CPG. Loading was determined by standard DMTr assay by UV-Vis (498 nm) to be 17 μmol/g.

Compound 23 (220 mg, 0.092 mmol) and diisopropylammonium tetrazolide (4.3 mg, 0.025 mmol) were dissolved in DCM (2.0 mL), followed by the addition of 3-((bis(diisopropylamino)phosphanyl)oxy)propanenitrile (60 mg, 0.184 mmol). The reaction was monitored by TLC. Upon completion, the reaction was quenched with saturate sodium bicarbonate (3 mL) and washed with saturate sodium bicarbonate (3×3 mL) and brine (3 mL). The organic layer was dried over sodium sulfate, filtered, and concentrated. The residual was redissolved in acetonitrile (3 mL) and washed with hexane (3×3 mL). The acetonitrile layer was concentrated and subjected to FCC using TEA/MeOH/DCM=0.5/0/99.5 to 0.5/6/93.5 to afford compound 25 (75 mg, 32%) as a white solid. Rf=0.3 in TEA/MeOH/DCM=0.5/5/94.5. ³¹P-NMR (mixture of diastereomers, DMSO-d₆): δ 146.366, 146.190.

Example 5. Preparation of Trivalent GalNAc Analog Compound 29 Attached to a CPG Solid Support

Compound 26: Adipic acid monobenzyl ester (48.2 mg, 0.204 mmol) was dissolved in DCE (1.5 mL) and TEA (0.11 mL. 0.816 mmol) was added. This mixture was stirred at room temperature for 5 minutes. Compound 21 (0.4 g, 0.204 mmol) was added, and the reaction mixture was stirred at room temperature overnight. Upon completion the reaction mixture was diluted with DCM (10 mL), and a solution of 5% NaHCO₃ (10 mL) was added with vigorous stirring. The organic phase was separated, and the aqueous phase was extracted with DCM (2×10 mL). The combined organic phase was dried over Na₂SO₄, filtered, and concentrated to dryness. The crude material was purified by flash column chromatograph eluted with DCM and MeOH (0% to 10% MeOH) to afford Compound 26 as pale-yellow foam (0.29 g, 69.0%). MS: found: [M+NH4]⁺=2086.3; calc: [M+NH4]⁺=2086.0.

Compound 27: Compound 26 (0.29 g, 0.14 mmol) was dissolved in a mixture of MeOH (2.0 mL). Pd/C (29 mg, 10 wt %) was added under argon purge. The reaction was purged with H₂ and was sealed with septum. The reaction was then stirred at room temperature for 1 h and was monitored by TLC. Upon completion the reaction the mixture was filtered through a celite pad, and the pad was washed with MeOH (2×5 mL). The filtrate was concentrated to dryness to afford carboxylic acid (0.22 g, 78.6%) as pale-yellow foam. This material was used without further purification. MS: found: [M+NH4]+=1996.4; calc: [M+NH4]+=1996.0. The above material (0.22 g, 0.11 mmol) was dissolved in DCE (0.6 mL), and TEA (61.9 μL, 0.44 mmol) was added. This mixture was stirred at room temperature for 5 minutes. 6-amino-2-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)hexan-1-ol (50 mg, 0.11 mmol) was then added, and the reaction mixture was stirred at room temperature overnight. Upon completion the reaction mixture was diluted with DCM (10 mL), and a solution of 5% NaHCO₃ (10 mL) was added with vigorous stirring. The organic phase was separated, and the aqueous phase was extracted with DCM (2×5 mL). The combined organic phase was dried over Na₂SO₄, filtered, and concentrated to dryness. The crude material was purified by flash column chromatograph eluted with DCM with 2% TEA and MeOH (0% to 10% MeOH) to afford Compound 27 as pale-yellow foam (0.22 g, 81.5%). MS: found: [M+2H/2+Na]⁺²=1228.1; calc: [M+2H/2+Na]⁺²=1228.6.

Compound 28: Compound 27 (220 mg, 0.091 mmol) and triethyl amine (14 mg, 0.137 mmol) was dissolved in DCM (2 mL), followed by the addition of succinic anhydride (12 mg, 0.120 mmol). The reaction was monitored by TLC. Upon completion, the mixture was concentrated and the crude was directly used for next step. Rf=0.2-0.6 in MeOH/DCM=10/90.

Compound 29: Compound 28 crude, 1000 Å LCAA CPG (0.30 g), TBTU (38 mg, 1.3 eq.), TEA (25.2 μL, 3.0 eq.) were dispersed in acetonitrile (1.5 mL). The mixture was placed on a rotovap and stirred for 2 h at 25° C. The mixture was then filtered, and this CPG was washed with acetonitrile (3×3 mL), THF (3×3 mL), and MTBE (3×3 mL), and dried to afford uncapped CPG. The uncapped CPG was then dispersed in THF (1.5 mL) with acetic anhydride (0.06 mL), pyridine (0.06 mL) and NMI (0.06 mL). The mixture was placed on a rotovap and stirred for 1 h at 25° C. The mixture was then filtered. The capped CPG was washed with pyridine/10% ethanol (3×3 mL), ethanol (3×3 mL), acetonitrile (3×3 mL), THF (3×3 mL), and MTBE (3×3 mL), and dried to afford desired CPG. Loading was determined by standard DMTr assay by UV-Vis (498 nm) to be 14 μmol/g.

Example 6. Preparation of Monovalent GalNAc Analogs Compounds 33 and 34

Compound 31: In a 100 mL round bottom flask, Compound 30 (684 mg, 1.38 mmol) was dissolved in DMF (20 mL). HATU (1048 mg, 2.76 mmol), DIEA (712 mg, 5.52 mmol) and 6-amino-2-((bis(4-methoxyphenyl)(phenyl)methoxy)methyl)hexan-1-ol (619 mg, 1.38 mmol) were then added. At room temperature, the reaction mixture was stirred for 4 hours. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (50 mL) and DCM (30 mL) was added. The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/MeOH (0% to 10% MeOH). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 30 (0.67 g, 68%). MS: found: [M+Na]=947.7; calc: [M+Na]=947.4.

Compound 32: In a 100 mL round bottom flask, Compound 31 (1.16 g, 1.25 mmol) was dissolved in DCM (20 mL). Succinic anhydride (188 mg, 1.88 mmol) and TEA (252 mg, 0.157 mmol) were added. The reaction mixture was stirred at room temperature for 12 hours. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (40 mL), and DCM (50 mL) was added. The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/MeOH (0% to 10% MeOH). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 32 (891 mg 78%). MS: found: [M−H]=1023.9; calc: [M−H]=1023.4.

Compound 33: In a 50 mL round bottom flask, Compound 31 (200 mg, 0.216 mmol) was dissolved in DCM (20 mL). 2-cyanoethyl N,N-diisopropylchlorophosphoramidite (61 mg, 0.259 mmol) and DIEA 83 mg (0.648 mmol) were added. The reaction mixture was stirred at room temperature for 2 hours. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (10 mL), and DCM (20 mL) was added. The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/TEA (0% to 10% TEA). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 33 (115 mg, 47%). MS: found: [M+Na]=1147.6; calc: [M+Na]=1147.5. ³¹PNMR (mixture of diastereomers, DMSO-d₆): δ 146.404, 146.228.

Compound 34: To a solution of compound 32 (1.50 g, 1.33 mmol) in anhydrous acetonitrile (100 mL) was added TBTU (512 mg, 1.60 mmol) and TEA (0.46 mL, 3.32 mmol). The mixture was stirred at rt for 10 min. Pretreated LCAA CPG 500A (20 g, 152 μmol/g) was added. The resulting mixture was slowly agitated at 25° C. for 3 hrs. The mixture was then filtered, the CPG was washed with acetonitrile (50 mL×3) and THF (50 mL×3) successively. The CPG was dried under reduced pressure for 3 hrs. Loading was determined by standard DMTr assay by UV-Vis (498 nm) to be 53 μmol/g before capping. To the CPG was added a mixture of Ac₂O (4 mL), N-methylimidazole (4 mL) and pyridine (4 mL) in anhydrous THF. The resulting mixture was slowly agitated at 25° C. for 1 hr. The mixture was filtered. The CPG was washed with THF (50 mL×3), 10% pyridine in EtOH (50 mL×3), EtOH (50 mL×3), acetonitrile (50 mL×3) and MTBE (50 mL×3) successively. The CPG was dried under reduced pressure overnight to give the compound 34 (21 g, Loading was determined by standard DMTr assay by UV-Vis (498 nm) to be 54 μmol/g). Ninhydrin test: negative.

Example 7. Preparation of Monovalent GalNAc Analogs Compounds 40 and 41

Compound 36: In a 50 mL round bottom flask, oxalyl chloride (0.64 g, 5.0 mmol) was dissolved in DCM (10 mL) at −78° C. under argon atmosphere. DMSO (078 g, 10.01 mmol) was added dropwise. The mixture was stirred at −78° C. for 20 minutes. Compound 35 in DCM (4.0 mL) was added dropwise, the mixture was stirred at −78° C. for 15 minutes, and then Et₃N (2.02 g) was added dropwise, the mixture was stirred at −78° C. for 60 minutes. After warming to room temperature DCM (40 mL) was added, and the organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product Compound 36 (˜0.8 g) was used without further purification. MS: found: [M−H]=476.5; calc: [M−H]=476.2.

Compound 37: In a 100 mL round bottom flask, crude Compound 36 (˜0.3 g) was dissolved in DCE (20 mL) at room temperature, Elinker (150 mg, 0.266 mmol) was added into the system. The mixture was stirred for 30 minutes, and NaBH(OAc)₃ (63.3 mg, 0.301 mmol) was then added. The reaction mixture was stirred at room temperature for 1 hour. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (20 mL), and DCM (20 mL) was added. The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/MeOH (0% to 20% MeOH). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 37 (100 mg, 41%). MS: found: [M+H]=911.7; calc: [M+H]=911.5.

Compound 38: In a 50 mL round bottom flask, Compound 37 (100 mg, 0.109 mmol) was dissolved in H2O (5.0 mL). Na2CO3 (57.7 mg) were added. At 0° C. temperature, Cbz-Cl (20 mg, 0.12 mmol) the reaction mixture was stirred at room temperature for 12 hours. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (10 mL), and DCM (10 mL) was added. The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/MeOH (0% to 10% MeOH). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 38 (101 mg, 87%). MS: found: [M−H]=1043.8; calc: [M−H]=1043.5.

Compound 39: In a 50 mL round bottom flask, Compound 38 (100 mg, 0.095 mmol) was dissolved in DCM (20 mL). Succinic anhydride (14.3 mg, 0.143 mmol) and TEA (19.2 mg, 0.19 mmol) were added. The reaction mixture was stirred at room temperature for 12 hours. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (10 mL), and DCM (10 mL) was added. The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/MeOH (0% to 20% MeOH). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 39 (71.2 mg, 65%). MS: found: [M−H]=1143.9; calc: [M−H]=1143.50.

Compound 40: In a 50 mL round bottom flask, Compound 38 (309 mg, 0.296 mmol) was dissolved in DCM (20 mL). 2-Cyanoethyl N,N-Diisopropylchlorophosphoramindite (139 mg, 0.591 mmol) and DIEA (190 mg, 0.648 mmol) were added. The reaction mixture was stirred at room temperature for 2 hours. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (10 mL), and DCM (30 mL) was added. The organic layer was separated, washed with water, brine and dried over Na2SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/TEA (0% to 10% TEA). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 40 (235 mg, 63%). MS: found: [M+H]=1246.3; calc: [M+H]=1246.4. ³¹PNMR (mixture of diastereomers, DMSO-d₆): δ 146.389, 146.221.

Compound 41: In a 25 mL round bottom flask, Compound 39 (41.2 mg, 0.036 mmol) was dissolved in MeCN (5 mL). HATU (13.7 mg, 0.0.36 mmol) and DIEA (14 mg, 0.108 mmol) were added. After 5 min, LCAA CPG (1000 Å, 1.0 g) was added. The reaction mixture was stirred at room temperature for 3 hours. After filtration GPG-41 was washed with MeCN (50 ml×3) and THF (50 ml×3), and then GPG-B7 was dried under vacuum. Cap A reagent: (THF/acetic anhydride/pyridine 80/10/10 v/v/v, 2.5 ml). and Cap B reagent: (1-methylimidazole/THF, 16/84, v/v, 2.5 ml) were added into the flask, and the mixture was stirred at room temperature for 2 hours. After filtration, GPG-B7 (after caping) was washed with EtOH (50 ml×3), EtOH/Pyridine (10%) (50 ml×3), THF (50 ml×3) and DCM (50 ml×3). The GPG-41 (after caping) was dried under vacuum. Loading was determined by standard DMTr assay by UV-Vis (498 nm) to be 39 μmol/g.

Example 8. Preparation of Monovalent GalNAc Analog Compound 45

Compound 43: In a 100 mL RB flask crude Compound 36 (˜0.8 g) was dissolved in DCE (20 mL) at room temperature, 6-amino-1-(bis(4-methoxyphenyl)(phenyl)methoxy)hexan-2-ol (Compound 42) (478 mg, 1.06 mmol) was added into the system. The mixture was stirred at room temperature for 30 minutes, and then NaBH(OAc)₃ (700 mg, 3.31 mmol) was added. The reaction mixture was stirred at room temperature for 1 hour. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (30 mL), and DCM (40 mL) was added. The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration, the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/MeOH (0% to 20% MeOH). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 43 (344 mg, 36%). MS: found: [M+H]=897.8; calc: [M+H]=897.4. Compound 42 was prepared according to methods described in Letters in Organic Chemistry, 2009, 71-76, which is incorporated by reference herein in its entirety.

Compound 44: In a 50 mL R_(B) flask, Compound 43 (344 mg (0.384 mmol) was dissolved in H₂O (5.0 mL). Na2CO3 (121 mg, 1.152 mmol) were added. At 0° C. temperature Cbz-Cl (71.7 mg, 0.421 mmol) was added to the mixture, and the reaction mixture was stirred at room temperature for 12 hours. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (10 mL), and DCM (10 mL) was added. The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/MeOH (0-10% MeOH). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 44 (65 mg, 16%). MS: found: [M+NH4]=1049.1; calc: [M+NH4]=1049.2.

Compound 45: In a 50 mL RB flask, Compound 44 (106 mg, 0.103 mmol) was dissolved in DCM (20 mL). 2-Cyanoethyl N,N-Diisopropylchlorophosphoramindite (36 mg, 0.156 mmol) and DIEA (33 mg, 0.258 mmol) were added. The reaction mixture was stirred at room temperature for 2 hours. Completion of the reaction was confirmed by TLC. This mixture was then poured into saturated NaHCO₃ (10 mL), and DCM (30 mL) was added. The organic layer was separated, washed with water, brine and dried over Na₂SO₄. After filtration the organic layer was concentrated to dryness under vacuum. The crude product was purified by column purification using DCM/TEA (0-10% TEA). The pure fractions were collected and concentrated to dryness under vacuum to obtain Compound 45 (60 mg, 47%). MS: found: [M+H]=1231.8; calc: [M+H]=1231.6. ³¹P-NMR (mixture of diastereomers, broad singlet, DMSO-d₆): δ 147.458.

Example 9. Preparation of Monovalent GalNAc-Conjugated Oligonucleotides

GalNAc-conjugated oligonucleotides were synthesized on a DNA/RNA synthesizer starting with a commercial DMTr-nucleoside-succinyl-CPG (1000 Å, Glen Research, Sterling, Va.). The standard synthetic cycle useful in assembling oligonucleotides comprise the steps of: (a) detritylation of the solid phase-bound material; (b) coupling of nucleoside phosphoramidite building block required by the sequence to the solid support-bound material in the presence of coupling agent; (c) capping of unreacted solid support-bound hydroxy groups with a mixture of acetic anhydride and N-methyl imidazole and (d) oxidation of the solid support-bound phosphite triester groups. The cycle appropriate for the assembly of the desired oligonucleotide was repeated as required by the sequence in preparation.

The final release of GalNAc-conjugated oligonucleotides from the solid support, deprotection of internucleosidic phosphates, and monosaccharide residues was carried out by treatment under the following standard condition. Upon completion of the deprotection under the conditions above, the liquid phase was collected and evaporated in vacuo to dryness. The residue is dissolved in water (1 mL) and analyzed by reverse-phase HPLC and by ES MS.

To demonstrate the usage of novel GalNAc-conjugated phosphoramidites in oligonucleotide synthesis, a sequence was designed for trials: 5′-X-TTTTTTTTTT (SEQ ID NO: 1)-3′, where X represents a GalNAc-conjugated phosphoramidite compound described herein. The following compounds were generated: Compound X1, Compound X2, and Compound X3.

Oligonucleotides (Compounds X1 through X3) were synthesized by solid-phase phosphoramidite method. A DMT-dT solid support was packed in an empty column and put into the MerMade 6 synthesizer. The synthetic scale is 0.5-1 μmol. The oligonucleotide synthesis cycle includes the following steps: (1) detritylation with 3% trichloroacetic acid in dichloromethane for 45 seconds two times, followed by acetonitrile washing; (2) coupling with 0.1 M DMT-dT-CE-Phosphoramidite (5′-O-(4,4′-Dimethoxytrityl)-thymidine-3′-cyanoethyl Phosphoramidite) in acetonitrile and 0.5 M activator (tetrazole in acetonitrile) for 1 minute two times, followed by acetonitrile washing; (3) oxidation with iodine (0.015 M iodine in water/pyridine/THF 2/20/78) for 45 second, followed by acetonitrile washing; and (4) capping with a mixture of acetic anhydride, pyridine, and THF for 45 second, followed by acetonitrile washing. Steps (1)-(4) were repeated 9 times for synthesizing a T10 elongated from the dT solid support. The final cycle to couple novel GalNAc-conjugated phosphoramidites includes the sample detritylation, oxidation, and capping step, while the coupling is using a mixture of 0.05 M novel GalNAc-conjugated phosphoramidites in acetonitrile and 0.5 M activator for 3 minutes for two times, followed by acetonitrile washing.

After synthesis, the oligonucleotide-bounded solid supports were treated with a 1:1 mixture of aqueous ammonia hydroxide and methylamine at 55° C. for 2 hr for cleavage and deprotection. Upon completion, the liquid phase was collected and heat dried in vacuum. The dried residue was dissolved in water and analyzed by reverse-phase HPLC (Agilent 1260) and LC-MS (Applied Biosystems 4000 Q-Trap). For Compound X1 and Compound X2, the HPLC gradient was 30-70% B in 20 min, with A: 50 mM triethylammonium acetate in water and B: 80% 50 mM triethylammonium acetate in water and 20% acetonitrile. For Compound X3 with C(Bz) protecting group, the HPLC gradient was 50-90% B in 20 min. The retention time (RT), MS calculated, MS found, and full-length product purity (FLP) for each sequence (Compounds X1-X3) were listed in Table 1 and Table 2.

TABLE 1 Usage tests of GalNAc-conjugated phosphoramidites in oligonucleotides with 30-70% B HPLC gradient Compound X (Phosphoramidite) Conc. RT (min) MS Calculated MS Found FT (%) Compound X1 Compound 15  0.1M 9.790 3493.2 3493.9 90.9 Compound X2 Compound 33 0.03M 7.311 3539.2 3540.4 5.4

TABLE 2 Usage tests of C(Bz) protected GalNAc-conjugated phosphoramidites in oligonucleotides with 50-90% B HPLC gradient Oligonucleotides X (Phosphoramidite) Conc. RT (min) MS Calculated MS Found FT (%) Compound X3 Compound 40 0.05M 14.677 3658.7 3660.6 70.5

Example 10. Preparation of GalNAc-Conjugated Oligonucleotides on Solid Supports

To demonstrate the usage of novel GalNAc-conjugated solid supports in oligonucleotide synthesis, a sequence was designed for trails: 5′-TTTTTTTTTT (SEQ ID NO: 1)-Y-3′, where Y represents a GalNAc-conjugated solid support. The following solid support bound compounds were generated: Compound Y1, Compound Y2, Compound Y3, Compound Y5, and Compound Y6.

Oligonucleotides (Compounds Y1-Y3, Y5 and Y6) were synthesized by solid-phase phosphoramidite method. A novel DMT-GalNAc conjugated solid support (Y) was packed in an empty column and put into the MerMade 6 synthesizer. The synthetic scale is 0.5-1 μmol. The oligonucleotide synthesis cycle includes the following steps: (1) detritylation with 3% trichloroacetic acid in dichloromethane for 45 seconds two times, followed by acetonitrile washing; (2) coupling with 0.1 M DMT-dT-CE-Phosphoramidite (5′-O-(4,4′-Dimethoxytrityl)-thymidine-3′-cyanoethyl Phosphoramidite) in acetonitrile and 0.5 M activator (tetrazole in acetonitrile) for 1 minute two times, followed by acetonitrile washing; (3) oxidation with iodine (0.015 M iodine in water/pyridine/THF 2/20/78) for 45 second, followed by acetonitrile washing; and (4) capping with a mixture of acetic anhydride, pyridine, and THF for 45 second, followed by acetonitrile washing. Steps (1)-(4) were repeated 10 times for synthesizing a T10 elongated from the GalNAc conjugated solid support and finished by the final detritylation with acetonitrile washing.

After synthesis, the oligonucleotide-bounded solid supports were treated with a 1:1 mixture of aqueous ammonia hydroxide and methylamine at 55° C. for 2 hr for cleavage and deprotection. Upon completion, the liquid phase was collected and heat dried in vacuum. The dried residue was dissolved in water and analyzed by reverse-phase HPLC (Agilent 1260) and LC-MS (Applied Biosystems 4000 Q-Trap). For Y1 and Y2, the HPLC gradient was 30-70% B in 20 min, with A: 50 mM triethylammonium acetate in water and B: 80% 50 mM triethylammonium acetate in water and 20% acetonitrile. For Y3 with C(Bz) protecting group, the HPLC gradient was 50-90% B in 20 min. For Y5 and Y6 with trivalent GalNAc, the HPLC gradient was 5-60% D, with ACN as D. The retention time (RT), MS calculated, MS found, and full-length product purity (FLP) for each sequence (Compounds Y1, Y2, Y3, Y5, and Y6) are listed in Tables 3, 4 and 5.

TABLE 3 Usage tests of GalNAc-conjugated CPG in oligonucleotides with 30-70% B HPLC gradient Oligonucleotides Y (CPG) loading RT (min) MS Calculated MS Found FT (%) Compound Y1 Compound 17 52 10.101 3493.2 3493.2 97.7 Compound Y2 Compound 34 54 10.417 3539.2 3541.1 97.0

TABLE 4 Usage tests of C(Bz) protected GalNAc-conjugated CPG in oligonucleotides with 50-90% B HPLC gradient Oligonucleotides Y (CPG) loading RT (min) MS Calculated MS Found FT (%) Compound Y3 Compound 41 37 13.154 3658.7 3661.2 72.8

TABLE 5 Usage tests of trivalent-GalNAc-conjugated CPG in oligonucleotides with 5-60% D HPLC gradient Oligonucleotides Y (CPG) loading RT (min) MS Calculated MS Found FT (%) Compound Y5 Compound 24 17 12.407 4742.8 4744.7 29.0 Compound Y6 Compound 29 13 12.906 4770.8 4774.3 27.7

While the present application has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made, and equivalents may be substituted without departing from the true spirit and scope of the present application. In addition, many modifications may be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present application. All such modifications are intended to be within the scope of the claims appended hereto. 

What is claimed is:
 1. A compound of Formula (I):

or a pharmaceutically acceptable salt thereof, wherein each of R¹, R², and R³ is independently hydrogen, benzyl, or —C(═O)R⁸; R⁴ is —C(═O)C₁₋₆ alkyl or —C(═O)C₁₋₆ haloalkyl; R⁵ is a hydroxy protecting group; R⁶ is hydrogen, a phosphoramidite moiety, —C(═O)CH₂CH₂C(═O)R^(6A), or —P(OR^(6B))NR^(6C)R^(6D); Y¹ is NR⁷, *NR⁷C(═O) or O, the asterisk * indicates that Y¹ is connected to L³ through the nitrogen atom of Y¹, provided that when Y¹ is *NR⁷C(═O), then L⁴ is absent; Z¹ is C(R^(Z)), P(═S), P(═O) or N, wherein R^(Z) is hydrogen or unsubstituted C₁₋₆ alkyl, provided that when Z¹ is N, both L⁴ and Y¹ are absent; each of L¹, L², and L³ is independently a bond, —C(═O)—, —C(═S)—, —S(═O)₂—, —C(═O)NR⁹—, —C(═S)NR⁹—, —C(═O)O—, —C(═S)O—, —NR⁹C(═O)NR⁹—, —NR⁹C(═S)NR⁹—, —OP(═O)(OH)O—, —OP(═S)(OH)O—, —O—, —S—, —NR⁹—, optionally substituted C₁₋₁₀ alkylene, optionally substituted C₆₋₁₀ arylene, optionally substituted C₃₋₁₀ cycloalkylene, optionally substituted 5-10 membered hetetroarylene, optionally substituted 5 to 10 membered heterocyclylene, or optionally substituted 2 to 15 membered heteroalkylene wherein one or more carbon atoms are replaced with C(═O), O, S or N, provided that at least one of L¹, L², and L³ is not a bond; L⁴ is optionally substituted C₁₋₈ alkylene; each of R⁷ and R⁹ is independently hydrogen, unsubstituted C₁₋₆ alkyl, substituted C₁₋₆ alkyl, or an amino protecting group; each R⁸ is independently C₁₋₆ alkyl, C₁₋₆ haloalkyl, or optionally substituted phenyl; R^(6A) is —OH, —OR¹⁰ or —NR¹¹R¹²; each of R^(6B), R^(6C) and R^(6D) is independently H, C₁₋₆ haloalkyl, or unsubstituted or substituted C₁₋₆ alkyl; R¹⁰ is unsubstituted or substituted C₁₋₆ alkyl, or a hydroxy protecting group; each of R¹¹ and R¹² is independently H, unsubstituted or substituted C₁₋₆ alkyl, or an amino protecting group; and each of m and n is independently 0, 1, 2 or 3, provided that m and n cannot both be 0; and when -L¹-L²-L³- comprise one or more C(═O), Y¹ is NR⁷, Z¹ is C(R^(Z)), and m+n=1; then R^(Z) is unsubstituted C₁₋₆ alkyl.
 2. The compound of claim 1, wherein Y¹ is NH.
 3. The compound of claim 1, wherein Y¹ is O.
 4. The compound of claim 1, wherein L⁴ is a straight chain unsubstituted C₁₋₆ alkylene.
 5. The compound of claim 1, wherein Z¹ is CH or C(CH₃).
 6. The compound of claim 1, wherein Z¹ is P(═O).
 7. The compound of claim 1, wherein Y¹ is *NR⁷C(═O) and the compound is also represented by Formula (Ia):

or a pharmaceutically acceptable salt thereof.
 8. The compound of claim 1, wherein Z¹ is N and the compound is also represented by Formula (Ib):

or a pharmaceutically acceptable salt thereof.
 9. The compound of claim 1, wherein each of R¹, R² and R³ is independently H, —C(═O)CH₃ or —C(═O)Ph.
 10. The compound of claim 9, wherein each of R¹, R² and R³ is —C(═O)CH₃.
 11. The compound of claim 1, wherein R⁴ is —C(═O)CH₃ or —C(═O)CF₃.
 12. The compound of claim 1, wherein each of L¹, L² and L³ is independently a bond, C₁₋₁₀ alkylene, or 3 to 15 membered heteroalkylene where one or more carbon atoms are replaced with C(═O), O or N.
 13. The compound of claim 12, wherein the 3 to 15 membered heteroalkylene is a PEG linker comprising one to five —OCH₂CH₂— repeating unit.
 14. The compound of claim 1, wherein m is 1 and n is 0, or m is 0 and n is
 1. 15. The compound of claim 1, wherein both m and n are 1, or both of m and n are
 3. 16. The compound of claim 1, wherein R⁵ is a trityl type of hydroxy protecting group selected from (4-methoxyphenyl)diphenylmethyl, bis(4-methoxyphenyl)phenylmethyl (DMTr), tris(4-methoxyphenyl)methyl, 9-phenylxanthen-9-yl, or 9-(4-methoxyphenyl)xanthen-9-yl.
 17. The compound of claim 1, wherein R⁶ is —C(═O)CH₂CH₂C(═O)OH.
 18. The compound of claim 1, wherein R⁶ is


19. The compound of claim 1, selected from the group consisting of:

and pharmaceutically acceptable salts thereof, wherein Ac is —C(O)CH₃, and R⁶ is —C(═O)CH₂CH₂C(═O)OH or


20. The compound of claim 19, wherein each of L¹, L² and L³ is independently a bond, C₁₋₁₀ alkylene, or 3 to 15 membered heteroalkylene where one or more carbon atoms are replaced with C(═O), O or N; and R⁷ is H, unsubstituted C₁₋₆ alkyl or an amino protecting group.
 21. The compound of claim 19, having the structure:

or a pharmaceutically acceptable salt thereof.
 22. A solid support comprising the compound of claim 1 covalently attached thereto via R⁶ of the compound of Formula (I), wherein R⁶ is —C(═O)CH₂CH₂C(═O)OH.
 23. The solid support of claim 22, wherein the compound is covalently attached to the solid support via a moiety:

wherein the dashed line refers to the connection with the solid support, optionally through an additional linker, and wherein the squiggly line refers to the point of the attachment of the oxygen atom that directly attaches to R⁶ of the compound, to the remaining portion of the compound.
 24. The solid support of claim 22, wherein the compound is incorporated into an oligonucleotide sequence.
 25. A method of preparing a synthetic oligonucleotide, comprising reacting a compound of claim 1, with an oligonucleotide.
 26. The method of claim 25, wherein the oligonucleotide has 1 to 100 nucleobase length.
 27. The method of claim 25, wherein the reaction is conducted on a solid support. 